Utter nonsense. Mandated treatment for drug addiction and severe mental illness would tackle half the problem.
Then provide contingent housing based on staying sober, sticking to your treatment plan, and getting a job. You can graduate when you’re able to pay your own way.
For non-addict/mentally ill homeless, it’s housing contingent on employment, graduate when you can pay your own way.
This would solve 90% of the problem.