What if WW1 happened 1950s because alternate Wilhelm II tries to maintain the status quo. Nicholas ii does the same like in OTL .Russia retains it's political system.
Given the situation in the early part of the 20th Century, it's vanishingly unlikely that there won't be a stumble into war at some point. There were many, many potential flashpoints, and there had been several near-misses before. Not enough people in high places were scared enough of a general war, and sabre-rattling when a crisis came around was par for the course. I once wrote a
modest article about a few of these near-misses (some of which would have involved different sides).
It's perfectly possible to sidestep the outbreak of war in August (or June, depending on when you count the start of the war) 1914. I do so in fiction (
Building Jerusalem, an 8 book series, of which the first six have been published. Book 1 is
Green and Pleasant Land). But the tensions between the various countries are still there, and the lessons that many of them have learned from the previous crises is that if you push and threaten war and sabre-rattle, the other side will blink first. Austria-Hungary had also learned that you can tear up agreements and get away with it (apart from pissing off potential allies who are pushed towards the other camp). What about Japan's growing ambitions in the Pacific? That's going to cause it to bump into issues sooner or later.
The idea that WWI won't have broken out by 1924 at the latest is a vanishingly small chance. There may well be changes of partners along the way, and it may not break out over the Balkans, but when so many people are waving lit matches about in a room filled with gunpowder dust, sooner or later, there's going to be a stroke of bad luck.
And, if we accept that by some miracle, WWI
doesn't break out, then there will have been so many butterflies by 1950 that the world will be unrecognisable. Has India become independent? There was the belief that Dominion status leading to Independence was in varying degrees imminent by 1914. Whether and how this develops will be complicated, to put it mildly. How does Home Rule go down in Ireland? Has that been resolved? How do Britain and Russia resolve the issues they had over Persia, and northern Persia in particular? What happens with the development of Socialism throughout Europe? Has decolonisation started? It had in OTL, but in the absence of two world wars shattering Europe, do the European powers maintain a grip? Or do they decide to go down the Dominion-Independence route quicker? Or do the accountants start analysing the cost/benefit equation of keeping certain bits of the world painted a given colour? What about technology? With no WWI, the technological drivers are different. Aircraft design received a huge boost in WWI. On the other hand, there are lots of clever people who in OTL died and who get to live and make changes in technology or art or politics or whatever.
Essentially, if one imposes the restriction WWI doesn't break out and there is "peace" until the 1950s, there are millions of vastly different versions of the 1950s available, and one can pretty much write whatever one wants.