To be fair, it behooves local governments to solve it. However, the moment a community does do something good, like UBI or small apartments, they get flooded with every other community exporting their homeless there.
Same goes for states as well. Any state gets inundated, and quality of help goes down.
And a national level plan has no traction. Capitalism itself implicates these people are just lazy and should help themselves. So there's no good (or any) national level plan.
And the business part of the economy (rich people) just want them to be 'away'. The term "Greyhound therapy" is precisely that - rich people/local govts will buy you a ticket to go somewhere else.
In the end, having these people with a home and stable living would ABSOLUTELY help local areas, and reduce massive burdens on services. But again, political will says these failures of the capitalist machine is somehow 100% their fault, and shouldn't be helped.