I don't really know what your point is. The amount may be a large dollar figure, but it is clearly not enough to solve the problem, therefore the problem still exists.
I'm curious how many people live in SF on 12-20k, but that's irrelevant. If someone has accommodation and is able to earn wages as a steady state, it is obvious that their costs will be less than a homeless person who needs mental health treatment, rehabilitation and maybe even education before they are employable.
The figure that employed people can survive on is well below the lower bound for what is needed to rehabilitate a homeless person.