While Bounty brings creators to ICO, good results in popularizing their token, of course they will exist. The problem is that every month more and more people take part in them and all receive less rewards than before.
Everything is unpredictable either tangible or non-tangible. If the cryptocurrency and ICo project still existed, bounty program will remain. It wont stop to helP ICo project to be successful to reach the goal. Only that everyday lots of new bounty hunters, rewards will be few.