There are other factors, too: The extent of the trading area is important. France suffered from high internal tariffs and duties during the 17th and 18th centuries, so even though she had a lot more population and arable land, she was overall poorer than the UK, which was one big free trade area. Political stability and the rule of law are vital. China had a very large internal free trade area with a lot of arable land and a large population, but as the 19th century went on her political stability fragmented and eventually disappeared.
Thing is, the alt-US will benefit from all the same things the UK does: It will be a gigantic free trade area, it will have access to the markets of the largest, wealthiest empire on the planet. Political stability and a strong rule of law are almost givens, if you look at other British settlement colonies.
Development is a guarantee and the extent to which a given place will develop is dictated by the supply of primary resources, which means arable land, mineral, and wildlife resources. The US east of the Mississippi has a vast amount of arable land, abundant mineral resources, and is extremely heavily forested in comparison to the Old World.
The problem is that the UK is benefiting from a not-US colony in a way that it didn't benefit from an American (and I use this word in absence of better ) rival. Even assuming the most lenient policy, more American money is leaving than OTL, more development is favoring British investors rather than American ones.
Is that to say that the US will not benefit at all? No. But there's a huge difference between a prosperous colony and a prosperous rival.
By 1900 the West represented a very small percentage of the overall American population and physical wealth. California had a scant 1.5 million residents in a time when the far smaller (in terms of land area) eastern coastal states of New York and Pennsylvania had ten times that much between the two of them.
The West, coincidentally for your argument, makes a far greater difference during the 20th century, as most of the Western states underwent very rapid development from 1900 onward while Eastern growth was comparatively more normalized.
Note to self: Dig up (pun not intended) figures on gold and silver production of California, Nevada, and Colorado. Same with any wealth from logging in California.
And then there's the Oregon territory and other things.
It would not be hard for North America to have more than two British colonies, even if we assume the Thirteen are one unit. Sticking this here for want of a better place to put it.
The states east of the Mississippi, in 1900, had a population comparable to the UK's population today. The UK population in 1900, on the other hand, was more like 38 million, versus the 54 million of the eastern US at the same time. So yeah, a lot of catching up to do, but they did it. Even if we assume the US gets no immigration over the course of the latter 19th century (a hilarious, totally un-realistic assumption), it's more than easy to posit that this is made up for by the lack of emigration of United Empire Loyalists after the Revolution and lives lost during the American Civil War, not to mention migration from Britain itself that would have gone to Australia, Africa, India, and Canada IOTL which instead goes to the *US. An eastern *US population of 45-50 million in 1900 is perfectly plausible. Anything less is implausible.
The US is somewhat less likely to be as attractive to say, Irish immigrants after the Famine in TTL. Possibly the same with others - it won't be that much different than Canada, so why go to the US? What makes it have more opportunities? Not much (looking at it from the "I've heard of, but never visited" view, where the US is known for being a place with British laws and liberties).
Nor is there any particular reason to go the US instead of Australia, Africa, India, and Canada vs. OTL.
Why are you assuming people flock to the not-US more than any other British territories (in North America or elsewhere)?
41.1 million, not 38.
And the opportunity did exist.
Assuming Britain a) treats "nonCanada" as one territory where "Americans" (we really, really need a better term here...help, someone...) are free to settle, among other things.
That issue of "the area being one colony" is more disputable than that there will be Anglophone settlement on both sides of the mountains, at least to me, but even the latter is not an absolute given.
What possible, realistic reason can you think of for the *US not settling the old Northwest and Southwest? If the Proclamation Line and the Indian Reserve are kept in existence, you can bet your ass there's still going to be a Revolution. This is really the essence of my point: Under any conceivable policy regime that keeps the American colonies from revolting and leaving the Empire, the *US is going to develop very rapidly and outgrow the metropole by the end of the 19th century.
Well, when your define "any conceivable policy regime that keeps the American colonies from revolting" based on "Any regime that doesn't treat the Americans with all the perks and none of the responsibilities of Englishmen within England", then its pretty hard. It is very doubtful that the Proclamation Line and the like are going to inspire a revolution on their own compared to for instance mishandling of the taxation issue, and this won't change significantly over time.
Grumbling and irritation amongst some? Yes. Every imperial policy on anything has inspired that. I don't think its possible to have a empire that doesn't have some people grumbling that the center takes no account of how their region is Speshul and needs to be given more priviligies and less taxes and other demands. Colonial or otherwise.
"They deny us land in the West! Restrictions on land ownership without representation is tyranny!" is...not going to go very far.
I suppose it's possible that you could say the *UK in this TL actively keeps the *US down, keeping the colonies in the Empire by force, but being forced to occupy the *US in this timeline would make the *UK itself poorer and less powerful in the long run.
The not-US doesn't have to be kept down by force, in the sense of a permanent military occupation on levels beyond (relative to what's being governed) India in order for British restrictions to influence how it develops.
Especially if the British (and settlers) treat the Eastern Thirteen as different than the Ohio territory (and later additions, if any).
This is factually incorrect. No large country in history has ever had the secondary sector making up a majority of output. In the US, for instance, manufacturing as a percentage of GDP peaked in the 1930's at about 30% of output. The hand-off wasn't from agriculture to manufacturing, but instead from agriculture to the service sector.
"Still, 'by itself the volume of total GNP has no important significance,', the physical product of hundreds of millions of peasants may dwarf that of five million factory workers, but since most of it is immediately consumed, it is far less likely to lead to surplus wealth or decisive military striking power. Where Britain was strong, indeed unchallenged, in 1850 was in modern, wealth-producing industry, with all the benefits which flowed from it."
That strongly indicates that growing industrialization and growing national wealth went together, in these circumstances.
What's really happening is you're falling for the same illusion that kept many third world countries drastically underdeveloped during the 20th century: They assumed fostering a large manufacturing sector would maximize national wealth, when in reality the tariff and internal industrial policies they followed in order to pursue that goal impoverished them.
No, what's really happening is that the "workshop of the world" is growing as fast and prosperously as it did because of increasing industrial development and things like the vast export of cotton goods.
That is increasing national wealth far more than say, what wheat is grown on the island.
The growth of manufacturing is something that happens after population density on the land has reached a point where there's no longer enough open land for settlement, the agricultural labor market is saturated, and wage laborers start seeking alternatives. You need a healthy, wealthy primary sector in order to support and sustain a growing secondary sector.
And Britain is already there, and making money hand over fist accordingly.
Russia actually would have been fairly wealthy if it weren't for the Tsarist tyranny on top. When the Russian Revolution toppled him, Tsar Nicholas was the wealthiest man in the world by far. Had the Russian peasantry been free to keep more of their surplus, they would have been some of the richest agriculturalists around at the time.
Russia's per capita GNP is terrible. In 1870 (the best year between 1830-1890), it is tied with the Habsburg Empire's figure for 1830. And 40% of the UK's. Despite a total GNP a bit over three times that of the Habsburg Empire in 1830.
Britain is two and a half times as rich, despite the total GNP being a little behind Russia (22.9 billion in 1960 US dollars and prices vs. Brtain's 19.6).
No matter how you distribute the tsar's personal wealth, Russia is (relatively) unproductive -and Britain very productive.
As an aside, however, the UK actually did surpass Russian GDP sometime in the late 19th century (1880's IIRC).
1880: 23.5 vs. 23.2. (UK vs. Russia)
1890: 29.1 vs. 21.1.
Any situation in which the *US decides to stay in the Empire isn't going to involve the British government taxing the *US for any benefits that accrue purely to the British Isles.
So, a scenario unlike OTL (where the taxation of the colonies was part of paying the expenses related to them) is unlikely to see the British Empire to retain the Thirteen. No one is disputing that.
But the British government taxing the colonies means wealth leaving said colonies and going to Britain for its purposes, even if "its purposes" include maintaining empire-wide defenses and such, its more money for Britain's spending.
Trade is not a zero sum game. If the US is importing from UK, it's also exporting to the UK. IOTL, the US essentially fed the UK workforce, and I see no reason this won't be true ITTL. American farmers are going to be some of the wealthiest members of the Imperial middle class, American planters some of the wealthiest members of the Imperial upper class. Importantly, both of these groups are going to be far more numerous than their counterparts in Britain.
Zero sum game isn't the point. The benefit of being the one selling steam locomotives and such products over the one selling corn or even cotton is another issue.
Thing is, I think it's ASB to have a situation where the US stays in the Empire and accepts a less favorable deal than they got IOTL. I know this point seems to fly over your head, but people don't just put up with being the oppressed appendage of an overseas empire, especially the comparatively well off descendents of a group of immigrants from that Empire's metropole.
I know that accepting that not everyone agrees that the colonists were oppressed is ideologically impossible, but that's not a reason to be rude. Nor are they getting a particularly unfavorable deal as a colony - just "suffering" from the fact colonies produce more wealth for the motherland vs. independent countries producing it for other independent countries, plus any British policies that lead to the not-US being smaller and poorer than OTL.
Its not as if people from TTL can say "Hey, Americans in the alternate world where we achieved independence are doing better than we are."
The *US will only still be in the Empire because the British government gave some kind of concessions to cool down the rising tempers of the late 18th century. A deal mildly similar to that Canada got 90 years later is likely, and that kind of deal is exactly what is necessary to allow the colonial economy to boom and eventually surpass that of the mother country.
Or if the British empire defeats the rebellion or handles the policies it did intend in a way less twistable by propaganda.
The colonial economy prospering and the colonial economy shooting ahead of Britain are two different things. It is much easier for the not-US to be the former than the latter.
P.S. Trying to make a point on the ideological comment. I'm trying not to say stuff like "You're incapable of accepting the legitimacy of the British government enforcing taxes" on the hopes that it means that we don't get bogged down in arguing that in this thread too, but your comment is really not a step in that direction.
Whether or not we agree on the justice of those taxes isn't the point, the point is that there were supporters of the British government within the colonies, as well as the "sons of Liberty" and other rebel-types. And their view prevailing would not take alien space bats or even an army of occupation.