I think a more common situation is that they are on the street because they are unstable, but being on the street makes it much worse.
See e.g. https://www.statista.com/chart/32585/change-in-median-rent-a...
The actual materials cost of a house, you can build one for $60k no problem and absolute shit-tons of cheap land near jobs (ex: unemployment extremely low in the Dakotas, cheap land, high demand for homeless-tier labor in the fields in bumfucklandia as ICE deports illegals making farmers desperate for anybody).