Most of the homeless people are just regular people. Sure, some of them have substance abuse problems.
But stand up in your cubicle when you get to the office on Monday morning. One of the coworkers that you can see from your desk has probably taken an opioid, cocaine, amphetamine, or a prescribed drug for ADHD or anxiety.
And they are fully functional.
Your coworkers are regular people. Just like the homeless that you see. More people than you know are one missed paycheque away from being on the streets.
Many of the "chronically homeless" as you call it are one medicine away or one therapist away from being fully functional. And one of your coworkers is one paycheque away, one bad week away from being chronically homeless.