I'm glad you pointed this out. I've had this thought floating around in my head for a long while. The only affordable high-density cities I can think of are in Thailand, Africa, and maybe Eastern Europe? I think NYC is our best comparison though... it's actually much more expensive per square foot to buy in Manhattan than it is in SF, and the rental prices are approximately the same.

Auckland, NZ is another example of a high density real estate hub gone bad. Mortgages are lower than rents but lack of housing stock.

Tokyo

Tokyo is consistently ranked as one of the most expensive cities in the world.

yet rent is less than half of that of San Francisco or New York

Japan has falling birth rate.

The rents in high-density areas of Seattle before the pandemic were about 30-50% less.

Singapore

https://m.youtube.com/watch?v=3dBaEo4QplQ

Singapore has public housing. You don’t own the unit. You lease it from the govt. I think it’s 99 year lease transferable.

Most residential units are not used or traded as a speculative asset.

[..] The majority of the residential housing developments in Singapore are publicly governed and developed, and home to approximately 78.7% of the resident population.[..]

https://en.m.wikipedia.org/wiki/Public_housing_in_Singapore