Drug-addicted and mentally ill people do not know how to keep even a moderately organized living space. Our city has tried "housing first" and it's been a disaster. The units are filthy, damaged, and the buildings don't pass minimal standards when the housing department inspects them because the "tenants" and their associates have destroyed them.
I do believe most SROs had a "no visitors" policy so that might help somewhat but there would have to be strictly enforced requirements about not trashing or abusing the property.