"Gosh what can we do about homelessness? It's such a desperately complex problem! If only someone had the solution, but nobody does!"
.... is a total lie.
Academics have known how to solve homelessness for 15 years (at least). The data is unambiguous. You solve homelessness by giving people homes. When you give them homes, then they are not homeless any more.
"Oh but the mental illness, the drug addiction..."
.... nope, bullshit. For starters, the majority of homeless people (people who currently can't afford accommodation) do not have a mental illness. And secondly, even if they did.... say they have depression.... do you think you can treat a depressed person sleeping under a bridge with talk therapy? Give them a home and they'll be less depressed.
The solution to homelessness is houses, just like the solution to hunger is bread and the solution to poverty is cash.