Passive Investing vs Active Investing Careers

What are the thoughts about those who choose a passive investing career? Is experience in passive investing pigeon-holing a person to only do that in their career? Or is there enough cross-over work where one can successfully make the jump to active investing down the road? Considering an asst PM role at essentially an enhanced indexing shop but want to determine what type of exit opps I may have a few years down the road…