Luxury apartments doesn't mean anything other than new construction. No one ever build super low end new housing in a desirable area, the land is too expensive. You need new construction like this to push down the value of existing housing.
https://www.lyonliving.com/santa-ana-california/the-marke
All of the buildings you're linking to are mid-rise developments with VERY low lot coverage dictated by local zoning. The look nice, but not that amazing compared to other new development around the country.
My point being, you can't just build cheap housing on astronomically expensive land, the math doesn't work. Crazy zoning laws add to that cost. Pointing to new development as the problem is simply wrong. If people want new construction at a lower level of affordability, then they need to change laws that drive up the costs of building. If the banks won't/can't loan money to a real estate project with an expected margin of return of < 3%, then what do you expect?
When you look at Eastern European population curves, most are flat. On the other hand, in half a century, California went from 15 million to 40 million people. In addition it built a HUGE agricultural industry that absorbs water from the entire western side of the nation. 1/3 of vegetables and 2/3 of tree nuts in the US come from California.
I wouldn't be surprised if California revitalizes in a few decades when they get their head out of their butts on housing. Getting rid of R1 zoning, building better transit, etc... Water on the other hand is going to be a problem unless South and Central America start growing a ton of tree nuts and drops the prices. (Probably in the smoking crater of what used to be a rainforest)