Nice analysis. However, be careful of the simplistic “too few working youngsters to support the oldsters” line of thought. A more nuanced approach, certainly applicable in Korea, is the dependency ratio (https://en.wikipedia.org/wiki/Dependency_ratio).
I live in Korea 8 months out of the year as an epidemiology teacher. I’ve seen some interesting speculation on causes for dropping births, and one that keeps popping up is English language learning. One of my students did a term project on the suicide outbreak at KAIST, a prestigious STEM school, and found that problems with English led to falling grades led to loss of scholarship support led to suicide.
Likewise, when teasing apart the high costs of child-rearing, the tuition for the private after-school academies looms large, and of those, English academies are the most expensive. It would be interesting and useful in policy terms if you could tease those factors out.
