Are these people completely insane? Shouldn't there be propositions for denser zoning, land reclamation, or other measures that would increase the SF housing stock? Houston has famously lax zoning laws, and as a consequence has seen much greater population growth (31% vs 18% from 1980-2010 per wikipedia) yet experienced none of these same problems.
The anti-development types are taking a very profitable position for themselves.
Houston's lack of zoning laws (there are HOAs, mind) has certainly created its own set of problems. A friend of mine once described it as less of a city and more of a vast collection of suburbs connected by strip malls - and that isn't entirely unfair.
Whether you view it as "horrible sprawl" or "affordable housing" sort of depends on where you sit, I guess.
And even for all that famous sprawl, Houston is seeing the same sort of urban in-fill that every other major US metro area is seeing... it just has a lot more land to fill before it achieves similar density.
However, the real problem is that San Francisco is water locked on three sides and boundary locked on the fourth. It has no way of adding housing that doesn't offend some entrenched interest.
What, and hurt profit margins?