South Korea went through an astounding period of economic growth. In 1961 its per-capita income was US$93 (inflation-adjusted). Ghana, one of the poorest nations in Africa, had more than double that (US$190). In 2024, Korea's had grown to US$36,624. That is almost 40,000% growth in a single lifetime. It is hard to conceive of in most places where GDP growth averages 1...2% per year. The difference between working hard to get ahead and trying to sit out and keep doing what you were always doing was literally the choice between affluence and destitution. So no wonder you have a population hyper-focused on their careers who pushes what children they have as hard as they can, so that none of them have any time for family now. The opportunity cost of anything else was enormous.

The positive news (if it can be called that), is that this level of growth cannot continue, so something will have to change.