China probably has no way out of its demographic dilemma, but many countries facing a similar problem do have the choice of more immigration. Canada’s one of the few that’s chosen to do so. The U.S., somewhat, although not as much as we used to. Xenophobia prevents too many countries from letting people in. Japan shows the demographic problems associated with immigration policies that are way too tight.
And at some point, there will be a "rush" to push it, meaning that rather than picking the team, it will be anyone who arrives is taken, which sets up more issues.