It's important to take into account the construction costs (and all the parties that are profiting from building new stuff). I think the cost of construction has gone up a lot in recent history. People in general also have much more luxurious requirements for housing than in the past which contributes to the cost. So, building just more is not some magical way to solve this. It's one efficient tool, however, especially if legislative point is made to strongly prefer affordable housing (and be strict about it).

Additionally cities earn more from commercial zoning than residential. And dense residential projects reliably get blocked by NIMBY neighbors. (NIMBY = Not In My Back Yard)

But this is not artificial.

This is a result of the fact that some resources do not have infinite space to increase supply. Land is one of those resources.

No matter how much someone demands it, we cannot simply wish more land into existence in SF.

So while we can increase housing supply by optimizing the usage of that land (more houses per unit area), this has adverse consequences for the people already using it...

> So while we can increase housing supply by optimizing the usage of that land (more houses per unit area), this has adverse consequences for the people already using it...

It would certainly have some kind of consequences for the people currently using it. Whether they would be better or worse that the consequences already being experienced is a matter for debate. I don't live in the bay area but would assume more density would largely be a good thing for regular people -- either their rent will drop because the market isn't so tight, or the home they own would rocket in value because it can suddenly be cleared to make way for an apartment or condo building (that they might have a hope of affording a unit in).

There are other people "using" the land though: the rentiers who run the local (and state, and national) government.