I used to take long night walks and runs in downtown Chicago when I was stationed there for training and would take the time to talk to homeless people after I bought them a meal.
You would be surprised and saddened at how many of them were normal hardworking people part of the same social/economic fabric that we are until they came up against a knockdown punch like medical bills/divorce/getting layed off and suddenly were out on the streets. And good luck ever getting off the streets if you find yourself there. It will pretty much take a miracle. Or people who care enough to make some change.