Totally false. There IS a permanent underclass of mentally ill and addicts, but in fact a huge amount of homelessness is composed of ppl who were mid-class or even rich & had several catastrophes happen at once (usually 2 of: divorce, job loss, death, and/or serious illness)
"Homeless" isn't a state of affairs; It's practically a separate breed of person and you have no chance of "becoming homeless" any more than you would become an NBA player.