Bingo...for most it’s a CHOICE. They either weren’t given the skills to survive and didn’t no where to turn to be a success, and by success I don’t mean being a millionaire, I mean just to be respected part of society, have a job, have a roof over their heads and generally not depend on the Government for hand outs. I get there are mentally challenged homeless but you have to ask how did they get there? Answer: By making bad choices in life
There are indeed a lot of people who end up on the streets because of their own poor choices. However there are also people who make poor choices because they don't have the mental capacity to make what most of us would consider good choices. Let me give you an example.
My aunt was schizophrenic. Her illness "blew up" when she was in her 40's. At that time she was married and the mother of 6 children. One day without notice, her husband took three of the kids and disappeared.
She'd always been kind of wacky, but fun to be around. Her husband's stunt pushed her over the edge. Anyway, she wound up not having any of her 6 kids. She was in and out of the VA Hospital in West Los Angeles several times and she did a couple of stints in Camarillo. When she was in care, she was on meds which stabilized her condition enough that she could sort of function in society. She'd go off her medication because they made her lethargic (this is common among schizophrenics).
For several years she had a tiny apartment in Venice Beach. One day, she walked out of the apartment and onto the streets for reasons that only she understood. She lived on the streets of L.A. and in and out of the hospital for the rest life, which remarkably lasted until her early 80's. So yeah, she made bad choices which caused her to be homeless, but she wasn't capable of making good choices.
Oh, and she would have nothing to do with any of her immediate family (basically her kids) for fear they would have her locked up. So even had any of them wanted to take her in, she wouldn't have let them.
Granted, my aunt did not represent all homeless people then or now, but there are a lot of people who are mentally disabled with literally nowhere to go but the streets.