> Tokyo, where a country-wide baby bust coupled with anemic local wages and a huge 1980s housing boom hang over, keeps things reasonably priced.

Nope. Tokyo's population is still growing, and 1980s housing in Tokyo is deeply undesirable. The reason Tokyo has sane housing prices is that it continuously builds large amounts of housing, because they haven't made it de facto illegal the way too many places have. Sometimes that's all it takes.