In one word? Apathy. Too few people are really invested in SF. If you're a resident of SF, you're busy working, partying, etc. Things aren't too bad and the money is flowing easily, so you don't care.
Things could be better if there was more home ownership and people put down roots here.
What you're saying makes sense. But it's kind of difficult to own a home when the cost of housing is so high and continuing to increase. From what I understand [1], there are laws that prevent high-rises (high-density residential buildings) from being built. With lots of people wanting to move there, simple supply-and-demand dictates that prices soar.
Things could be better if there was more home ownership and people put down roots here.