Most of the developed world has this problem, in fact. The only places where it is less evident are those where they receive enough immigration from developing countries.
Once the “developing world” eventually joins the “developed world” and begins to suffer the same declining birth issue, we are going to have to rethink our model of economics to accommodate for a shrinking global population of workers. The good news is that AI and automation might solve that problem for us, but we will have to see who can actually integrate these solutions responsibly, without consolidating all of the financial resources towards wealthy oligarchs who own the technology.