What would be the economic, political, and technological development if there's no World War I and II.
Would Russia remained capitalist and czarist?
Would Argentina remained a developed nation?
Would Japan and Korea poorer than in OTL?
Would South Asia remained united?
Would Communism and Populism evolved without World Wars?
Would the World more capitalist than in OTL?
Would Africa poorer than in OTL?
Would Atomic bomb developed without World Wars?
Would Space and Computer Age happened without World Wars?
Would Facism and Nazism evolved without World Wars?
Would Europe less populated than in OTL?
And last, what would be the life of Adolf Hitler without World War I and II?
Russia: Probably not. A crisis was brewing in Russia--land reform, merchantist power and a quasi-divine royal family don't mix well. I would expect either a deal or a coup that winds up with moderate leftists in charge--Russia starts to move down a Swedish path of development, although it might face ongoing pains trying to control areas like Poland and Finland from people who don't want them there.
Argentina: Don't know a lot about them; there would probably be no Justicalist movement since Fascism would be fringe. It should be pointed out that Argentina played little role in WW2 and while it copied Fascist movements OTL doesn't mean that it has better ideas this time around.
Japan + Korea: While there would be no WW1, Japan is undoubtedly interested in expanding into China and building its own empire. Japan probably makes it into the developed nation's club--but Korea, and possibly China as well are colonies for the Japanese economy. I'd like to quickly add that even Japanese Domination is probably better than North Korea's current regime, so perhaps the answer is that Japan would be down, but not out.
South Asia: With no WW1 and WW2, the UK is probably going to be in India longer. The UK might have its enthusiasm for empire cooled, but no world wars and its decline might be not only more graceful but also slower. India is the jewel in the British Empire, and I see the UK being able to wrangle some kind of dominion deal with India as the price of independence. It would be a very different ballgame, and it might go down spectacularly badly if the UK simply refuses to let go...
Without the Red Revolution in Russia, Communism is entirely different than OTL. It might be a dream of stary eyed idealists, or it might play much nicer than someone like Stalin did OTL. Populism, or people power, is probably moving faster than OTL since no wars result in a peace dividend, more domestic focus, and because national security is much less of an issue. Yes, some nations like the Ottoman Empire and Austria Hungary are going to meet their end in the 20th century--but perhaps later, in a more amenable way than being forced to concede at the barrel of a gun.
A more capitalist world? Hard to say. The effect of a respectable socialist movement instead of post Ww2 "Welfare States" could well lead to a more socialist world; particularly since the political left isn't demonized for half a century.
The flip side is there is no great depression (or if there is one, it is euphemistic compared to OTL's disaster) and the Keynesian notion of economics might never take off. The world also has more money, so the issue of redistribuion is less touchy. If people aren't starving at the bottom of the lineup, they'll be less insistent on getting a larger cut.
Africa: Africa is going to poor no matter what happens. The basis of Africa's problems--its arbitrary borders, lack of infrastructure and dismal if not depressing leadership--is not directly tied to the World Wars. Yes, the west may pull out of Africa with more consideration for Africans themselves--but then what? Even Liberia, which should have a deep inherent understanding of how to function as a country, has been to seriously bad dictatorships. The West will never be altruistic enough to subsidize Africa if it feels like holding onto it is a mistake, and if the West wants to hold onto Africa, they'll be hard pressed to let go. The World Wars forced the UK to recognize that they couldn't pay the bills, and they wore down France's willingness to fight--further, the sins of Germany, Japan and Italy to a frightening degree were inspired the the UK, USA, and France. If there are no world wars--is colonialisation ever discredited?
The Atomic Bomb is definitely developed, and it is also probably used for something like a colonial revolt--and proves to be much more effective than intended. Indeed, the calculations of making an atomic bomb are frighteningly easy to do today; they weren't that serious an affair in the 1970s eiither. However, the idea of MAD would not exist, so it is entirely possible that a world war might be possible and much more painful than many would expect. (It always is, actually)
Space Age: Probably not. While Communications is probably going through, the idea of landing on the Moon is probably seen as an expensive waste of tax dollars. With no cold war (heck, given the situation, the United States might well have a tiny army and comfortably napping while a still dominant UK struggles onward with two thirds of its empire in its hands), there is not only no impetus for a Space Program, there is no defense budget to do it.
Computers: Probably ten years earlier. The effect of business, not the armed forces, taking the lead would probably have accelerated computer development slightly.
Fascism: Benito Mussolini is a dedicated Socialist with no War Experience; it is either butterflied or it is something entirely different.
Nazism: Anton Drexler is a kook. Hitler never joins the German Army, but Drexler's oddly oxymoronic "National Socialist German Worker's Party" remains the bizarre name of an equally bizarre party. Drexler continues to head the organization, which never even adopts the evocative term "Nazi" in the first place.
Europe: Europe is up something like fifty million without the World Wars and Stalin. Furthermore, with the UK, Soviet Union and Germany all bombed out, there would be little emigration and more children. Europe would be up perhaps 10-20% in terms of population.