> at present the best Chinese scientists are still coming to the USA to work
IMO not true anymore. This isn't pre 00s where PRC send best abroad as part of state strategy and best have some english fluency because it's needed for science. More and more PRC best aren't English fluent since there's sufficiently large and growing chinese science ecosystem and best also have good access to resources in tier1 labs. Hence US cracking down on 1000 talents program where PRC entice scientists to work in PRC due to unparallel resources. Or acadmeic exchanges with PRC in general. Also see stats of record amount of scientists returning to PRC this yearm
>best students want to stay there,
Best PRC students go to PRC C9 (Ivy equivalent) now. Top US institutions captures the occasional talent with english proficiency and desire / resources to go abroad. But PRC best have been largely staying in PRC last decade. TBH most Chinese students in west now are those who couldnt hack PRC gaokao/teritary selection system but have rich enough parents to send them abroad. They're B tier talent. Still adequate to work in western labs but you simply don't hear much about PRC students in west who tested top of their districts anymore like in 00s. They're no sending their best and haven't been for while. But generally their ok is good enough. Medium term expect even less PRC students, partly due to geopoltics but also PRC likely phasing out mandetory English as core subject which will make brain draining next gen more difficult. There's always India who seem systemically incapable of preventing brain drain.