Agreed littering is cultural, but if e.g. 1/1000 people do it then it's also very much a function of density. If we're going to increase density we need to be even more proactive about sanitation, trash, noise, and "misbehavior" or edge cases in general (crime, mental health, etc.).

Strongly agreed on alternatives to driving, and I'd throw in "truly accepting remote work" (not just being "remote friendly but you should take a global trip with us every quarter"). We have a global telecommunications network, we ought to use it.

Supply chains, local food, and not overstraining our watersheds are also all key. We'll have to face the reality that some cities are just built in a way/place that they don't belong, at the size they are at least.