We could fix the whole SF homeless population problem in the space of one parking lot. Just build micro apartments of 10'x10' feet. Make it 150' wide at the base: 15x15 = 225 x 40 stories = 9000 inhabitants. 100' feet might not be much, but it's a hella of a lot more space to live in than hong kong, where people barely get one bed.
And, with SF's enormous homeless budget of over 300 million, combined almost over 500m? there'd be more then enough funds to build as many of these buildings as we need.
The thing that stops these types of solution is rules, rules and more rules. We choose not to solve the homeless situation: it's a political choice.