Conversely, I know several couples who have gone back, especially after child rearing. What people want is far more complicated that "single family homes", but

Conversely, I know several couples who have gone back, especially after child rearing. What people want is far more complicated that "single family homes", but a range of preferences. Most prefer a detached home from any thing non-detached. Most prefer access to good schools (while/if they have school age children) opposed to poor schools. Most prefer being close to work over a long commute. Most prefer easy access to cultural/social aspects of a city over not having access. Etc. etc. Every buying choice is a set of tradeoffs unless you are almost unfathomably wealthy (20m detached home in a dense city with a helicopter pad ticks a lot of boxes). I think a lot of focus not so much on "vertical housing" but density and "missing middle" housing is just the fact that current (US, anyway) city design is hitting some walls, and "more of the same" isn't going to work.