"Basically what I'm saying is, that by 1914, there's no reason to think that the Empire would not continue to dominate both trade, maritime matters and industry for a looong time... With its colossal Empire, Britain had all the customers, workers, soldiers and resources they could ever want!"
Then why would it have lost WWI without US help?
"Hence by 1922, and even with a sustained fight, the Brits could, and I'm not saying they necessarily would, take on the US in an naval war and win!"
Gaps of 2:1 and rising in industrial production can't be overcome in a long naval war. You are free to think differently, of course.
"Regarding the GDP btw I couldn't find data for the rest of the British Empire in 1914, so I used the 1900 numbers (which was easily accessable ), and it's quite clear that the Empire's economy is huge compared to the US."
Even in 1900 and using your +$500 pc figure for Britain alone, the British economy is much smaller than the US, since it's population is half the size. By 1914, the US economy is more than twice as large. In dollar values, the contribution of rest the empire is small -- though this may certainly be misleading since most assets are off-market. Of course, including the empire would lower Britain's pc income a great deal, making it appear much poorer.
"Noooo... The nominal GDP of the US in 1929 was 103,6$ and it was 126,7$ in 1941. And if you read the article it's fairly obvious that Field believed that the US economy grew quite a lot in that periode. Source: http://www.eh.net/hmit/gdp/gdp_answer.php"
That's 1941 and I cited 1940 (twice). I don't appreciate your repeatedly mis-stating my claims. For 1929 on, use the Survey of Current Business. An on-line series is given at:
http://www.bea.gov/bea/dn/gdplev.xls
Pre-1929, the authoritative source is Historical Statistics of the US, but that isn't available on-line without payment. EH has a calculator which isn't primary data but which is handy:
http://www.eh.net/hmit/gdp/
I think you are referring to that in your link, but your address is not quite right.