> A lot of this had to do with the rise of Nazism which led to a lot of these high powered intellectuals fleeing Germany and Eastern Europe for the US.
The Nazis managed to drive out a large portion of Europe's best scientists & mathematicians (Von Neumann, Einstein, Gödel [eventually... it took him a while to realize how bad things were] just to name a few). Most of which ended up in the US or the UK. Which in turn meant that in WWII Nazi Germany was at something of a scientific disadvantage without realizing it was of their own making. Add to this the Nazi critique of of what they called "Jewish science" - things like relativity, quantum mechanics, even Gödel incompleteness theorem got this label - did not allow them free inquiry into many of these areas.