While most of the nation is still trying to claw its way out of the deep economic crater left by the recession, this onetime steel capital is already out—thanks largely to the relentless growth in healthcare jobs. Partly because of the outsized ambitions of the University of Pittsburgh Medical Center, the healthcare industry has replaced manufacturing as the region's powerhouse. About 1 in 5 private-sector employees in the Pittsburgh area today works at a hospital, a doctor's office or in some other health services business. Among the concerns: overdependence on a rapidly shifting industry, huge nonprofits that don't generate much in tax revenue, and a business model that exacerbates the disparity in income among workers in different but similar jobs.