Is this number missing a zero? That sounds very reasonable for use of land and 24/7 security. And at $5k a month I'm not sure how many apartments you can afford. Or is that meant to be $60k per tenant? How many people can you house in one of these sites?
That’s the point the original article made - they were throwing money at short-term shelters and other things, just like everyone else and the problem got worse not better. Instead, doing stable housing first and applying conditions later allowed people to adapt. I suspect that they also get to re-use units the NGOs bought to house next set of people once the initial occupants have improved their situation enough.
If one were to use the $2100 for mortgage payment as well, with taxes/hoa/insurance included, that would finance over $400k worth of unit.
SF also has the BMR program that’s designed to provide ownership opportunities for low income people. If NGOs with State backing could be involved, BMR inventory could be an interesting starting point. Then you could provide additional incentives to developers to include even more BMR units, etc.
*There's a popular analogy with crayfish traps here in Finland wrt. one individual finding their way out of the trap, only to have the other crabs pull them back in.
Even if it means say a parking lot for 20, that seems pretty crazy. You can just give $2k to buy an apartment, if you are puritan and have to control whether or not they spend it on substances just pay the landlord directly. Probably has to be a place that can get cleaned up easily though after they move on.