This is a question to which I haven't found a satisfying answer yet: why do old houses look better than new ones?

There are answers like "only good looking houses got preserved" or "it's just perception, in a hundred years people will love the houses being build now as much as the houses which were build in the nineteenth century". I don't really buy such arguments. I had some musings about people no longer caring about living in a beautiful house because with fast transportation there is less incentive to make a good impression on your neighbors. Or maybe it's something about craftsmen making less design decisions because of more planing and prefabrication. But these too are just speculations.

Are you just musing to yourself? That is, is your question "Why do old houses look better [to me] than new ones?" or are you polling the public?

If you're polling the public, taste is a real thing too, modern architects have a different aesthetic. Same shows up in clothing: a simple waterproof polyester jacket from uniqlo vs a hand-sewn trench coat with a million features like epaulets, grenade rings, gunflaps, etc.

Nice, I lived in a 1+5, I didn't know they had a name.

TBH the quality was good enough. Sound could be quieter but was fine. The biggest problem was sprinkler system, at least once a year there would be a leak or a trigger that would completely destroy 1-3 apts. I dream of concrete now.

I don't see the problem. Could quibble about styling, but that is an order of magnitude nicer than the surface parking lots or 60s shitbox apartments that currently dominate Los Angeles.