Taiwan not far behind, but with a smaller population to start with.

Domestic policy seems to be hard to fix since it requires a massive cultural shift that may take a generation and requires big changes in the economic structure (income, employment law, child care capacity, etc.) that are going to have push back from corporations.

Immigration is also a bit of a challenge as SK, Japan, and Taiwan are all a bit xenophobic to extents and of course, the languages are not easy to gain proficiency.

I also think that this generation of people just think differently on matters of child rearing and what it means in life. (East Asian elder millennial w/2 kids). Even if money were no issue, I wouldn't want more kids.

Will be an interesting couple of decades.

The community-selected title by the “Dearrow” browser plugin is “The long-term effects of South Korea's unprecedented fertility crisis”, which is a better title.