This happened in Oregon a few years ago: any cities with 25k or more people had to permit greater density. I'm optimistic about housing on the West Coast for the first time in a long, long time. This will transform things in a big way.
It happened in WA two years ago as well, but Seattle dragged its feet as long as humanly possible in implementing a compliant zoning policy.
https://www.theurbanist.org/2025/05/27/seattle-just-rezoned-...
Oregon - thanks to governor Tina Kotek - pushed those reforms further this year:
https://oregoncapitalchronicle.com/2025/07/29/gov-kotek-sign...
I got to play a small part in that, going to Salem to say my piece in favor:
https://oregoncapitalchronicle.com/2025/03/04/oregon-gov-kot...
She liked my hoodie!
https://bsky.app/profile/tinakotek.bsky.social/post/3lkea36k...
That said, what her bills have accomplished is a bit different than CA: rather than larger buildings close to transit, we legalized 4-plexes and a variety of other housing types that use land more efficiently, throughout cities.