As for (1), flip it around and it’s more realistic (how much of their work in industry or as RAs has subsidized America?). The benefits are in America’s favor still. As for (2), I spent 9 years there and find my experience invaluable. I could have done it elsewhere though, well, it was nice. There weren’t many of us, especially if we are just talking about Americans and not other westerners. But, as an example, one of the best SR/ML researchers I know got his chance in China even though he was European.