I grew up in Eastern Europe (Warsaw) in "commie" blocks and there was a lot of valid criticisms and problems (like poor quality of buildings, small apartments, or thin walls - but consider that they rebuilt whole Warsaw after it was completely grounded in WW2 in a decade or two!), but also a lot to love. Extremely walkable, safe, all amenities (cinemas, stores, cultural centers, playgrounds) in the walking distance, lots of trees and green, easy access to public transit. As a kid or teenager they were great. I preferred it 100x over suburbs where my parents moved later, and to typical American cityscapes. (And this is why I moved to NYC and love it)
Here is a fun and a bit provocative/exaggerated video https://youtu.be/1eIxUuuJX7Y
Everyone is different so I'm not forcing my perspective onto anyone, just worth considering - especially if you have not had such first hand experience (and the main objection to tenements comes from how depressing they look or American association of "projects = crime", which misses a lot of "why"). Feel free to disagree!
And apart from that, I don't think "more of small houses" solves anything. It has to create more car dependence and social isolation. And it does not really scale, where would you fit more of smaller homes in SF?