In California one thing that could be done is cut out a few of the insane laws that create homeless people out of people who are marginal.
Three examples I know of:
A friend of mine lost his home in a divorce. Then he lost his job. Someone gave him a twelve foot camp trailer. He was able to talk some people who owned a small trailer park into letting him park next to the restrooms so he would not have to walk so far.
Along comes the man with the code book: "Buddy you can't live in a camp trailer that doesn't have a bathroom." The owner of the trailer park was fined and the camp trailer impounded.
He moved out to the rock piles where a bunch of homeless people lived. Living in a small group they had more protection than they would as individuals. They showed him how to cobble together a hut out of cast off cardboard boxes.
Along came the men with the warrants: "The businessmen in town have petitioned the city that you folks are a blight on the community so by order of this paper we are burning up all your boxes."
More recently a couple I know fell into bad times with money and could not meet their mortgage payments. They had a simple solution. Let the daughter, her husband, and their children, take over the house and the parents would live in the fifth wheel.
The gal with the code book came along. "You can't live in a fifth wheel. You have to end the situation now or else."
So now the parents are homeless.
A few homeless people were living under a huge tree that afforded them some protection. The last plant manager where I work, and some other "good people" got together to have the lower branches of the tree cut so it would not afford any protection -- So we can have a "better" community.
Multiply that a few thousand times.