?They kept doing the same things behind the iron curtain in Eastern Europe for decades after.

Nazis' mistake was they started invading. Made their way to USA & got their asses kicked. But allies weren't able to stop it entirely so "nazis"/soviets/ commies (all same) agreeed to stick to their half of the globe for some decades and that's how we got peace. Some of those countries still are the same.

I think had Nazis stayed in Germany, nobody would've done anything.