Take Paris or Berlin with their 5-8 floor buildings as far as the eye can see. That's a moderate density for a modern city, leaves space for green spaces, infrastructure and is so dense that everybody can sort-of affort it while not so dense that everybody is just anonomous. You can still know all neighbors in your building by name. (That there is a problem with exploding rents is a separate issue.)
As contrast, take the average north american city with a million residents. most either live in a detached house or in a 30+ floor skyscraper. Of course the detached houses rather close to a city center won't have much space around them, so you hav 1.5 bushes and then there is the fence and next house. The lots are worth millions and out of reach for most unless the go super deep into debt and have a lot of luck. Or you live in an anonymous skyscraper silo. There is an alternative to all this, but all that's happening is that excuses are ruminated back and forth.