The people with the power (money) to do so have no incentive to do so because they hold real estate which keeps going up because of the shortage. Why work against yourself?
It's like a prisoner's dilemma where property owners as a class may not want more housing so that they are wealthier on paper, but any individual property owner will want to build housing because that'll grow their wealth faster.
Here in Oregon, we're making some progress on housing reform. The mayor of my city attended the YIMBYTown conference a few years back when she was a city councilor. Heck, the now-governor of Oregon, Tina Kotek, spoke at it, and continues to work on housing policy.
Part of the puzzle is that reforms are better at the state level, where it's easier to say "yeah, we have a housing crisis, and these things will fix it" and you're not confronted by a local angry mob of NIMBYs intent on stopping homes from being built.