It's really not all that complicated: it's the homes, stupid.
I live in the central valley, which dominates California's y-axis; it's home to a lot of the California cities you may have heard of but have no idea where the fuck they go in the map, like Modesto or Fresno. Here's the point, the central valley kinda sucks, nobody should be excited about living in Modesto for any reason, ever. We don't have skyscrapers and beaches here; we have shitty air quality, cows, and perpetually angry farmers. That hasn't stopped rents from absolutely exploding in the 11 years I've been here. Rent in podunk ass Los Banos (Pop ~40,000 rounding up, bedroom community for bay area commuters) has cleared $3000 a month for a pretty standard suburban home, and clears $2000 for a small two bedroom. Only it's not just Los Banos, it's everywhere.
This isn't rocket science, folks; it's econ 101. You have more demand than supply, your prices go up. Well, not only has California not been adding to it's housing supply over the years, but we've had cities actively fighting any efforts to build anything that isn't single family homes. I spoke to someone at CA YIMBY (Yes In My Back Yard) who told me that San Jose shot down some 98% of proposed high-density housing because they wanted to "preserve the small town feel of San Jose". Ah, yes, the small town of San Jose. More than that, though, every step Newsom has taken to try and get more housing built has been viciously opposed by (mostly bay area) municipalities. Imo, it's because with property values utterly divorced from reality, it's stupid easy tax revenue; plus their landowner buddies are taking in rent hand over fist, so they have all the incentive in the world to preserve the status quo.
You want to fix homelessness in California? Start plunking down commie blocks. I'm dead ass serious, pick a city block and just put 400 housing units on it with room for a couple of commercial units on the bottom. Now do it again, and again, and again, and don't fucking stop until landlords are forced to compete and stop, I shit you not, demanding essays from prospective tenants in their lease application.
"but conditional soup, you can't make me live in an affordable communist box." First of all, shut your mouth when you talk to me. Secondly, I never said I would make you live in a commie block. People who value paying an affordable rate to be able to stay of the street will rent the commie blocks; people who don't mind paying extra to get extra will still rent single family, but they'll still be better off because those rents should come down, too.
"But people don't want to live like sardines!" <- Statements dreamed up by the utterly deranged. Nobody wants to be homeless, either. I think between an affordable sardine can and being homeless because single family housing costs too damn much, I'd take the sardine can. Most people would.
Of course, like anything that would fuck up the money printer to make people's lives just slightly less miserable, it's a really controversial take in practice. People act like building more housing is literally the ghost of communism. Instead we should be doing infinite studies on the causes of homelessness, funding enormously expensive programs that frankly only help a few people, and go on generally trying to make life so miserable that maybe the homeless will just vanish some day. Will affordable housing fix all homelessness? No, of course not, but it is enormously helpful in addressing the problem, and it won't even start to get better until we do something about the housing shortage