One of the reasons California has such a huge, problematic, homeless situation is it's too expensive to live in many areas, many mentally ill and rebellious people who don't want to work "for the man", but most of all, it's the beautiful weather.
It's harder to live on the street in Arizona because it's hotter than hell there, while in New York, there are 4 seasons but no problem, because social services are great. Plus you do have people going around getting homeless into shelters on the worst winter nights.
The point is, many homeless in these places don't originate in these states, but can get 'lost' there, once arrived. They are not interested in mainlining into society.