"Connection to your neighbors"? When low-density housing means that houses cost several million dollars apiece, that means you're trying to preserve the "uniqueness" of the city center for a bunch of millionaires. I fail to see why I should care about them.

Low density housing doesn't mean million dollar pricing in a lot of cities. When a neighborhood of single-family homes is torn down to make duplexes and condos, the connection between neighbors is certainly broken. The neighborhood can also lose the appeal that drew residents in the first place.