> If cities would just build simple housing with proper sanitation (tiny houses, SROs, whatever) to get those people off the street

I don't think it's that simple. This isn't a fixed constant set of people living on the street that you find homes for and that's the end of the problem.

It's more of a revolving door; there's a constant supply replacing whoever gets off the street.

I think what the article mentioned about Seattle is actually a reasonable approach:

  Seattle, meanwhile, has allowed some tent cities to operate as de facto communities —
  long-term, regulated, even with phone numbers and addresses.

That might be a good compromise. Provide enough infrastructure to be sanitary, like California's state campgrounds with hot showers and toilets, with the addition of mailing addresses. Give them enough stability to maintain a job and a state ID, but don't make it so comfortable as to incentivize exploitation. It's a difficult balancing act, effectively helping the homeless, without making it an attractive path of least effort.

Except there is no infrastructure beyond what can be accessed via a cell phone - these are strewn along highways or streets, or beneath overpasses, unless there are some that really are more formalized than I've seen yet.