Weakening them in 1974 if anything seemed to restrict supply.

SF has comically low density housing that is driven by homeowners lobbying to restrict development.

The difference between SF and Seattle is probably property taxes (higher in Seattle). It discourages land from being hoarded and used unproductively.

Then when rent controlled unit can be redeveloped, there's a desire to allocate various percentages to different income levels. This means that some units have less income for the same cost so it's hard to balance meaning fewer projects get off the ground.

Now there's even further issues about development as a right vs requiring a use permit...

So, there's a lot of contributors, but the political impact of the politics of rent control is significant.

[0] https://www.berkeleyside.org/2021/07/28/uc-berkeley-settleme...

and yet to keep up with demand we would've needed to more than 3x what we did, though from what I understand, the infrastructure to build more high density housing even faster just doesn't exist. Seattle was literally building housing as fast as it is possible for a US city to build housing.

If true that, in my opinion, points to a more significant problem in America.