One has to consider history though. European top researchers crossed the Atlantic due to the war and later because it was more stable than Iron-curtained Europe

One has to consider history though. European top researchers crossed the Atlantic due to the war and later because it was more stable than Iron-curtained Europe, but now that a lot of factors have settled there’s probably less brain-drain into the US from around the world. The social problems mounting up in the US affect all this too. Granted, not noble laureates, but anecdotally I know a couple of Europeans in the sciences who decided to move back to their home country because they found life in the US stressful