There is a lack of affordable housing in all US states.
It's extremely hard to live without a car in the US and cars are a huge expense, plus our car-centric culture means lack of a car is a barrier to employment, both practically and because people are reluctant to hire you.
Medical expenses can be a factor in the US. Universal health coverage could help.
There's no one cause and the oft cited "addiction and mental health" is largely prejudice. In a nutshell, you wind up homeless when you have too many problems and not enough resources to handle them and the US doesn't provide a robust social safety net.
Is it a lack of affordable housing or is it a lack of wage growth compared to cost of living?
Personally, I've started to think it's the latter, because it explains why upper middle class non-millionaires are also getting pinched. They too often rely on income rather than capital gains.
My personal conspiracy theory, and I admit it's a conspiracy theory, is that corporate land owners are the ones centering popular conversation and data around affordable housing rather than wage growth. It opens doors for rental assistance, a multitude of rental-based density expansions, and other programs that put more money in their pockets rather than expanding the money income-based people make and keep via ownership.
In the 1950s, the average new home was 1200 sq.ft. Post 2000, it was over 2400 sq.ft. and held on average one less household member. We've also torn down a million single room occupancy units in recent decades.
My house was built in the 1950s at around 1200sq ft. It's since expanded to over 2000, mainly from finishing a basement and expanding the top level. I'd be curious to see the data you base that on, because the people I bought it from passed this down generation to generation and had their entire family living in it. The house I grew up in has a similar story.
Another anecdote is that about half of the 1950s homes on my block were bulldozed and replaced with single units that have largely gone vacant. My cities issue is that we have plenty of housing, but even the bottom line single units are too expensive compared to wages because permitting and building costs are through the metaphorical roof.
Between 1955 and 2013, almost one million SRO units were eliminated in the US due to regulation, conversion or demolition.
https://en.m.wikipedia.org/wiki/Single_room_occupancy
I'm pretty sure the stats on 1950s housing vs. post 2000 housing were federal stats, but I don't have a citation handy. I've been talking about housing issues a lot of years.
In Texas I don't remember seeing much if any SROs. I've only seen them in abundance since I've lived in Portland.
Land owners aren't really incentivized that much to talk about affordable housing. Housing developers would like to fix the problem by building market-rate housing - as supply goes up, demand begins to be satiated and prices can come down over time. All the while, developers make more money.
But building dense and inexpensive housing is often blocked by leftist-type politicians for being unsuitable for living, and NIMBYs of all sorts of political spectrum block it on wholly different grounds.
More housing = affordable housing. Not subsidized housing, not regulated housing. Just more of it will help America.
> More housing = affordable housing. Not subsidized housing, not regulated housing. Just more of it will help America.
Last caveat that I'd add to this is also more diverse housing street by street. Having space for single family homes alongside dense housing isn't just a good vibe, I think it also incentivizes a normalization of value. Combine that with shopping/retail and I think you can build some pretty equitable places with shorter commutes.
Something like ~97% of people live on ~3% of the land.
This is evident, for example, if you look closely into the studies saying stuff like "most homeless people in the Bay became homeless in the Bay area", etc.