And it remains messed up to this day - some countries get to be under their own nuclear umbrella, while others don't.
This kind of selective distribution of superpowers doesn't lead to great outcomes
Relative to what?
There's this trend in history that every hundred years there's a giant blow up, lots of violence, followed by peace.
It's likely that we would have had 80 years of relative calm due to that cycle even if nukes hadn't happened
to WW1 and WW2.