More than anything, homelessness is about precipitation. 
Reagan intentionally destroyed public housing efforts. Business was actually encouraged to move out of the US, so that investors could reap massive benefits. I remember when America, pre-Nike,  had a shoe industry, for example. City after city destroyed low income housing, calling them slums. The draft was ended, so many low income males didn't have that to help them find a trade. College became the path to, if not wealth, at least a job, but now poor people are being priced out of that alternative. 
So quite naturally, people who were poor but previously had slums to live in were now falling out of the economy.  City after city accumulated thousands of people who had been broken and tossed to the curb. 
We became multiple Americas, and the people at the top have all the resources. 
It's a "Blade Runner World" raining despairing, outcasted people.
Hugh Massengill, Eugene Oregon