Something the other replies didn't mention is that some (many?) homeless people wouldn't be hired for minimum wage jobs because they'd be considered overqualified. [0]

There's always the option to leave education and employment off of your resume, but during the interview how do you explain even a four-year gap without mentioning "I was doing a Ph.D in particle physics" or "I designed marketing materials for Goodyear"?

[0] For example, a "Emmy-award-winning, New York Times bestselling author and Harvard grad cannot land a job as a greeter at The Container Store." http://www.scarymommy.com/club-mid/the-illusion-of-control-o...