I've never been involved in these programs on either side, but it's amazing that $70k/year might not be enough to house somebody.
But how many of those 7000 homeless need that level of care? Half? 2/3? SF should at least be able to get the "easy" people off the street.
That doesn't surprise me at all. There's a homeless guy in my neighborhood I've been talking with at least 7 years. He has mentioned being born at the hospital 3 blocks from my place, and I'm sure he grew up in the neighborhood. He's polite, friendly, and very set in his ways. I suspect he has some sort of alcohol-induced anterograde amnesia. He has absolutely no interest in living in any sort of setting where he'd be constrained by others. From the way he talks about it, I expect there's some sort of history of abuse by authority figures.
I don't think it's impossible for him to get help. But I think it would have to include living in his neighborhood and I think it would need a lot of patient and intensive help from professionals. Otherwise he's just going to do what's familiar to him.