I don't have a nutshell answer for you.
Part of it is that housing policy here has serious issues. We have changed zoning, etc, such that it is nearly impossible to build the kind of walkable communities that existed in this country before the automobile took over. The New Urbanist movement tried to build walkable communities. They found it very challenging to get such plans approved at all.
Another piece is that we don't have good health care policies. Most people on the street in the US have some kind of health issue, whether medical or mental health. Our policies in the US don't do a good job of providing for such people. Most developed countries have much better policies for dealing with people with serious issues of that sort.
Here are a couple of my blogs if you want to try to read through them, though I don't know if that will really answer your question:
https://streetlifesolutions.blogspot.com/
https://sandiegohomelesssurvivalguide.blogspot.com/
I would like to see the affordable housing shortage tackled and the health care issue resolved. I think if those issues are not resolved, basic income will likely actually make things worse for poor people who will then get dismissed as not trying hard enough, not managing their UBI, etc. I think giving UBI to people in the current American climate will just mask the real problems and make people who are comfortably well off even more callous about "Not my problem. It's just a personal issue and the world isn't obligated to fix your personal issue."
I already get told on a regular basis that the housing crisis isn't really a problem. It isn't a problem for the well-heeled, so they don't see why others find it so monstrous and impossible.