East Asia, in general, has severe demographic issues. I think South Korea actually has even lower fertility rates. I've read that if the current fertility trends continue, East Asia is facing the most rapid intergenerational population decline in human history. The current record holder is the Americas after small pox arrived.

As bad as the brain drain is, it could easily be much worse. I went to grad school with many brilliant Chinese students who almost all were hoping to get academic jobs in America, because our current visa system would then let them stay indefinitely. Most of them would have been happy to take industry jobs in America, but then they might get deported if they don't win the visa lottery. The result is that enormous numbers of brilliant Chinese graduates have to go back to China every year, despite wanting to stay and employers wanting them to stay.