> The decline of Germany as the leading scientific powerhouse in the first half if the 20th century

Go on? WW1 and its consequences?

I think the educational policies are most interesting to compare. There was systematic attrition of academic talent driven by xenophobic ideologies. It started slowly and well before the 1930's, before it turned into an all-out purge. There was also ideological alignment of academia in multiple ways. The timing might not perfectly line up with what we're discussing now, but it definitely qualifies as within-lifetime, and I think the overall parallels are interesting.

WW2 and it's consequences will be a big part of this.

Consider the Oppenheimer movie. The majority of physicists depicted there are people who left Europe around that time.

It's this: https://news.ycombinator.com/item?id=49210165