Probably because people are free to migrate anywhere within a country's borders, so cities with lots of social services get overrun with a disproportionate amount of people wanting to use them. These sorts of policies need to be implemented at a nation-wide level for them to be truly effective.
"Thing that fails in the small scale needs to be implemented on an even bigger scale" is a hard sell. How do you convince a state that thinks California is a hell hole that they should implement Californian policies in their own state? This doesn't seem possible to me.
If there can be a politically practical solution at all, I think it must be one that can be demonstrated to work in the small scale.
> How do you convince a state that thinks California is a hell hole that they should implement Californian policies in their own state? This doesn't seem possible to me.
First step would be to identify the specific things that make California a hellhole v. the things California gets right.
If I put myself on a starvation diet and still starve to death, it doesn't follow that the solution to hunger is to eat even less. Obviously, the solution to homelessness is homes.
If you implement them nation-wide the only result would be people coming from abroad to enjoy housing-first social services. Unless you are saying the first step towards solving homelessness is the prevention of illegal entry and the mass expulsion of illegal immigrants.
I get the impression there's a fair chunk of America that feels that way about any sort of government-provided assistance (though more accurately I guess it's "assistance is fine as long as it's to people I approve of).
Cities that have done treatment first policies have seen a reduction homelessness.
A great book on this topic is San Fran-sicko. https://www.amazon.com/San-Fransicko-Progressives-Ruin-Citie...