Homeless folk in America; once they're homeless is that it for them, no chance of work or renting an apartment?

It's almost impossible to get out of. I know a chick, mother of two, who ended up living in her car for a few months. Eventually she got some istance and managed to get an apartment but it's still touch-and-go. She went from a well-paid professional job to minimum-wage telemarketing, and her homelessness had a lot to do with that.