Another aspect-- a lot of desirable places to live have populations that literally and directly state they don’t want to build more dense housing, they don’t want people who can’t afford the sfhs to live there.
That’s true, but I think that’s largely because they feel it’s necessary to protect their main investment. As you said, owning real property is one of the best ways into the middle class. For many Americans, their home is their most valuable asset, by far. People want to maintain these restrictive zoning laws because they feel it’s in their financial best interest to do so.