From a national standpoint, it's housing, but SF (and Oakland) specifically has a much different problem. The politicians run their political experiments in SF

From a national standpoint, it's housing, but SF (and Oakland) specifically has a much different problem. The politicians run their political experiments in SF and they completely ignore the secondary and tertiary effects. You can't make it easy for people to live outside and not think it will not attract people from all over the country. Now it's guaranteed they won't have enough housing because of all the people it has attracted. Otherwise there's no reason to go to an expensive city if you can't afford it.