That number is self-reported and ostensibly includes crashing on someone's couch for a month before getting kicked out. (IIRC, the head of Department of Homelessness and Supportive Housing admitted as much recently on Michael Krasny's Forum show.) Plus, most forms of public assistance require being a California or San Francisco resident. The legal definition and logic of residency doesn't translate easily into non-lawyer speak, so like with many such things there are common myths about meeting residency requirements, such as having lived in a place for at least 1 year, etc.[1] And it doesn't matter that the legal requirements are rarely enforced, people needing assistance will often follow a script.

If you know anything about how evictions work in this city, like the fact that Ellis Act evictions require a _ridiculous_ amount of compensation (think at least $20-$30k), it's obvious the real problem with homelessness in the city is drugs and mental health and the fact that, for whatever reasons, homeless from around the Bay Area, California, and Western U.S. inflate our numbers.

My mother is part of a jobs program that pays her to tend to some disabled people in public housing[2]. That is, she's intimately familiar with many assistance programs from the perspective of both beneficiary and provider. In San Francisco, if you live on the streets but are willing to enter treatment (for mental health or drugs), it's _very_ easy to be housed. It's actually a source of resentment because plenty of people who could really use public housing, but who otherwise work their butts off to stay off the streets, can't get it in favor of people who can get housing (plus cash benefits) merely by stopping drugs.

Drug and mental health issues are legitimate problems that people need and deserve help overcoming (often in perpetuity), and I don't have a problem funding programs to help those people. But IMO using the housing crisis to explain street homelessness is self-serving and counter-productive rhetoric by people effected by high rents, who have every incentive to link the two problems considering that the city actually puts resources into addressing homelessness. The cost of housing no doubt plays a part at the margins (e.g. by taking extremely low-end housing off the market that once upon a time might have been more tolerant of drug addicted and mentally ill tenants causing trouble and missing rent), but based on the facts on the ground I can't see how it's even close to being the primary cause of the magnitude of the problem today.

[1] It doesn't help that during the 1990s many states, including California, tried to make many of those myths the law, but SCOTUS shot them down (I think because of the Privileges & Immunities Clause). Still, Republican pundits today still push for hard requirements like 1 year of residency, having had a job, etc. This lends the myths credibility and keeps them circulating.

[2] Disabled in a very technical, legal sense. Every one of her "clients" is at least as physically capable as others of similar age. Most disabled in these programs are people who, because of psychiatric or cognitive issues, simply have trouble taking care of themselves or mastering life skills more generally, even if in conversation they seem perfectly normal and intelligent. The public housing they live in would deteriorate into garbage dumps and drug dens if people didn't come in and clean up after them and tamp down on bad behavior Involving police or social workers would be far too expensive, and such blatant exercise of authority would drive these people back out onto the streets. IOW, you literally need to _pay_ these people to stay off the street. Humans are... complex....