As amazing as it seems, a lot of far left people in the Bay Area who engage in the housing debate actually don’t believe in supply and demand. Hard to have any kind of discussion on that basis.

I believe that, on average, housing prices increase when housing is limited and decrease when it is not. I don't believe this relationship is nearly as linear as people imagine, especially since not all "demand" for housing comes from people wanting to live in it (thanks to rampant speculation in the market). I also don't believe that even a tremendous increase in available housing will cause the price to decrease enough that rent is actually affordable for the people who currently depend on rent control, and I am not willing to treat those people as "collateral damage" in the quest to lower housing prices in SF.

If we built lots more housing, there are two mutually exclusive possibilities (though honestly, they are on a spectrum):

A) Housing becomes affordable, or B) housing stays expensive.

The latter means we added trillions of dollars to the national wealth.

By the way, please go ahead and do tax property a lot. Ideally, you'd only tax the unterlying land with a land value tax. But even a naive property tax is OK.

That way foreigners buying up local real estate for speculation means foreigners paying for local services.

The government is perfectly capable of paying for housing if it is so inclined. It is also capable of providing incentives for creating new housing in certain markets, such as discounts; the idea that this can only be incentivized by charging new and existing tenants insanely high rents is the problem. Perhaps it could get some of the money required to do this by extracting it from the tremendous number of wealthy people living in SF, many of whom are probably browsing HN right now. It would likely be easier to do that if their rents weren't so astronomical, of course...

As for "does not translate to affordable housing"--right now landlords and property developers have two ways of extracting money from the system: charge high rents, or pass the property on to other landlords. Maximizing profit on either of these requires rents to keep going up, and for the second there's no particular reason to actually have tenants. Beyond that, "market rate" in SF right now is nowhere close to affordable for most people and will not be for the foreseeable future, even if building greatly increases, which means that the people currently protected by rent control--those who can't afford "market rate", like the vast majority of people in the U.S.--aren't helped one bit by the creation of new housing.