The point of my comment, in response to its parent, is that people in the US are willing to support immense amounts of money being spent on the homeless as long as it doesn't involve housing anyone.
I think the institutional structure of most US states and cities wouldn't blink at spend huge amounts on schizophrenia drugs as long as it doesn't involve any kind of inpatient treatment (forced or not) that would put a roof over anyone's head.
The core issue with homelessness is one of how our modern capitalist socieites are laid out.
In order to have a life, you must have a job. This is the underlying assumption that fuels everything. This assumption has a critical flaw: not everyone can have a job.
For some segments of the population, we just "bolt on" fixes to this fundamental problem. 401k's so that workers may still get their money when they no longer work. Foster care, so that abandoned babies who cannot work can still live.
For the severely mentally ill and drug addled, we haven't figured it out. The reality is these people cannot work a job and most will never be able to work steadily. Advancements in drugs may help, but even then there will always be some segment of the population who simply cannot work.
Previously, we took an "out of sight, out of mind" approach. Institutionalize these people. It's cheap, particularly if we treat them like dogs. We've evolved and realized such an approach is inhuman and evil. Now, though, what do we do?
If these people had a basic income available, they could at least pay to help themselves. This isn't a silver bullet, but I believe it's better than the current problem we have.
The true solution is fixing the fundamental problem modern society has: everyone has to work. This is really hard.
go talk to a sample and you'll quickly find out it ain't the lack of home.