Like so many young Americans, Derek Wetherell is stuck.

At 23 years old, he has a job, but not a career, and little prospect for advancement. He has tens of thousands of dollars in student debt, but no college degree. He says he is more likely to move back in with his parents than to buy a home, and he doesn't know what he will do if his car—a 2001 Chrysler Sebring with well over 100,000 miles—breaks down.

"I'm...