As long as new projects and coins enter the cryptocurrency world, as well as this forum exists, Bounty programs will run. These new projects and old projects which wish to refine their strategies need the help of bounty hunters to spread the awareness across all over the globe.
Bounty hunters are not only confined to ICO there are services that offer bounty rewards but as long as there are ICO there will always bounty campaign because it's cheap and bounty hunters are willing to accept tokens instead of coins that already has value in the market.