The US benefited from such a scientific talent immigration trend after WWII. The European theoretical physics community is benefiting similarly from LHC and the short-sighted cancellation of SSC. Any area of research that requires massive, long-term, blue-sky funding will be dominated by governments willing and able to provide it, and will attract the best talent from all over the world.
The major problems China will face in this instance will be the language barrier and reticence of some scientists to work for a more authoritarian, censoring government. The former is easily solved, the latter is problematic but not insurmountable - even scientists have their price and plenty would convince themselves to work under such a regime in the exact same way Google did (change it for the better by 'engaging' it), especially when the alternative is a stagnant career and dead-end research due to lack of funding elsewhere.
This conceit that many in the US and West have that the quality of our science and research is innate and unimpeachable is both ignorant and complacent. Where there's a will there's a way, and China certainly has the will.
