And a very basic part of it is simply geometry: the more people you have in a limited area, the harder it is to build homes for all of them. Historically, there simply were FAR fewer people, and so finding place for homes was never a huge issue. The cost of housing is mostly property, not construction costs.
The US is huge with a low population density, why not just expand the cities a bit or build a few new ones? Is there some reason why this can't be done?
> Throughout his campaign, Trump focused on deregulation, tax cuts and reducing mortgage rates. In speeches, including one at the Economic Club of New York in September and a press conference in August, Trump reiterated his promise to reduce regulatory barriers and vowed to make federal land available for extensive housing projects.
https://www.housingwire.com/articles/trump-housing-build-fed...
And while it is a magnet for this kind of problem, San Jose and Los Angeles have similar issues.
Part of the problem being, they’re one of the easiest places to be/exist if you’re homeless. Not that it’s necessarily easy or pleasant, but compared to Chicago, New York City, or some random suburb? You bet.
It's this trifecta that people complain about - unsheltered, mentally ill and addicted. If we can solve any one, that feeling of abject squalor goes away.
That's why they say capitalism is based in fear. That's why we have dreams of Star Trek.