It's actually quite high. 10%+ in this meta-analysis, and 21% with some form of psychosis.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6880407/

If I were to guess, I would say that while many people may experience bouts of homelessness, the ones with schizophrenia are more likely to be persistently homeless.

this is completely true, but they take up a very disproportionate amount of time and energy from social service providers, people who work in shelters, etc, and make all spaces for homeless people much more chaotic.

the crisis would look very different if it was just a mix of people dealing with drug addiction (but basically lucid and rational) and with poverty.

"drug addiction (but basically lucid and rational) "

Serious drug addicts are seldom lucid and rational.

But I very much do get the point, that solving the schizophrenic problem, would help a lot with everything else. (I am just way more sceptical, that this drug can deliver that)

Even those who are not, will probably develop some sort of schizophrenia due to their marginal lifestyle, but I wonder if it's really a "disease", I feel like it's an adaptation to their environment for people who are more sensitive than others. I feel like the pain is more due to the lack of solutions, especially in a city centre, where it's a constant hell for these guys (and for most any other animal actually, except a few who adapted to that: pigeons, rats, some insects but not the most beautiful ones), just my thought

> but I wonder if it's really a "disease"

Not a disease but a real illness, with no cure but treatment like cancer.

Even with effective treatment, sometimes the psychosis wins, and the patient can backslide into full blown illness.