Michael Preiss was happy to escape the corporate grind after being laid off by International Business Machines Corp. in 2001. He became a contractor, earning more than $100,000 a year from steady assignments helping companies figure out how to do things faster and cheaper.

That work eventually dried up. The past decade has been a revolving door of outsourced jobs for shrinking pay, fear that any day at a company could be his last, and reminders that full-time employees live in a different world, even though they often sit...