This is definitely part of it - people are born in Tokyo, live in Tokyo, and plan to die in Tokyo. Coupled with much stronger cultural norms around not being a

This is definitely part of it - people are born in Tokyo, live in Tokyo, and plan to die in Tokyo. Coupled with much stronger cultural norms around not being a pain in the neck to strangers and respecting public amenities, this changes the calculus for whether or not you’re going to trash your city.