What criterion do you suggest to determine who lives in SF, besides "let people come to mutually beneficial arrangements among themselves"? Keep in mind that the most common alternative policy, rent control, is widely acknowledged (http://www.nytimes.com/2000/06/07/opinion/reckonings-a-rent-...) to turn rental markets into basket cases.
There are currently a host of policies that keep people from doing what they would otherwise very much like to do, which is building new higher-density housing and living in it. That would result in net gains, whereas arguing about who gets to live in SF is pretty much zero-sum. Yet people really seem to like to argue over the latter, and are weirdly quiet about the former.