It continues to strike me as odd that there isn't more focus on building high-density highrise housing in SF. Is this related to earthquake danger, historical preservation, idiocy on the part of local politicians, or some combination of these?
Secondly, there is no upzoning, and subsequently no increase in density, without eviction, thanks to the rental market. Evictions aren't popular. The Tenderloin is completely insulated from any of this.
Historical preservation is bogus, but has a history. The reason that some people argue for largely have to do with the projects in the Western Addition, which bulldozed a bunch of victorians to make what most people consider an eyesore.
Local politicians don't really care too much. The reason being is any action they take pissed off established residents, who voted them in. That's changing a bit, as more people feel the pressure of the rental market and evictions. Still, there's more of an attempt to protect people who are established then there is an attempt to accommodate those who actually need housing, especially those in the middle class.
1) Buy a house for their kids studying in the US; 2) Launder their money; 3) Own a property outside of China as an investment; 4) Have a safe house in case they need to flee the country.
The bay area is a popular choice for such people due to the high concentration of Chinese immigrants / Chinese Americans already living here.
I'm not passing judgement, just presenting facts from personal experience.
And I have friends in the Peninsula who have such crashpads in the City (unfortunately, I didn't win the IPO lottery like they did).
So I'm not blaming "furriners" or "1%", just stating what my limited experience has been.
The problem is further compounded by the zoning laws, parking space related laws and the local community which is consistently voting against any housing projects to make sure their property rates do not go down because of increased supply.