I have stayed and visited japan for the last 35 years, and find all of the "Tokyo is so affordable and buildable" is hilarious. The breathless articles I read about it leave out fundamental aspects (the incredible density, the absolute destruction 70 years ago, the corruption [especially in Shinjuku], the size of the "livable apartments", the need to rebuild anything from before 1980 for earthquake safety, that youth population falling by half, the stagnation of wages), and the fact that most people who can leave Tokyo to raise children do (even if it means commuting 2hrs each way every day on a train).
This just doesn't match anywhere in the US or frankly almost anywhere else in the world. I know 2 people who actually still live in Tokyo. One is a 28 year old single foreigner, and the other is stuck in a 100 year mortgage with their extended family. All the rest moved.