The US was also much more unified at the time. That’s the thing about history: Like economy, it’s human matter, and you could reproduce and experiment twice and get completely different result because your systems are not isolated in location or time.
>The US was also much more unified at the time
Were we? Or is that just after the fact revisionism that makes things "easy"
If Europe had managed to keep it together a few more years the US may very well have had a bunch of communism adjacent social strife and FDR may have died a deposed tyrant.
We were certainly more unified on certain broad cultural and values axis, but things were still very divided.