China is especially interesting since it appears that much of the housing stock was built purely to be a financial instrument, and was never occupied.

There are entire towers that were never used as residences, but just used as investment vehicles based on faith rather than any sort of realized value.

This is really a story about the dangers of using housing stock as an investment vehicle.

North America has a related problem of financialization, but is complicated by rules constraining stock in the places where people would like to live.

I would argue that you need rules around financialization (punitive capital gains taxes on market based gains for non primary residence), as well as rules around allowing people to do reasonable things with their property (infill, single family zoning, etc) to increase the amount of allowable stock.