City demographics are changing. I think it will become viable soon. Most San Franciscans are tired of filth and squalor, and moving the dependent population onto land cheaper by a factor of 100 is compelling.
A lot of the issue is that people rich/smart enough to move to SF now (vs. those who pre-existed) value education. They're not going to send their kids to SF public schools, so they move to Hillsborough or Palo Alto for the schools. That leaves a population of 20-30s childless people, who are more likely to be liberal, and old hippies, the same.