I can recall that this question has been asked before. The need for bounty programs is a result of releases of new ICOs. These ICOs must be advertised all over the world for patronage. Bounty hunters cashed in on this job and keep themselves busy. So it will continue as long as new ICOs are released and this forum is continued.
It might be that your opinion is mistaken because let's say public ICOs will stop to be profitable and prohibit any advertisement on different forums and social networks for some reason - bounty will disappear. In any case, I do not know enough to claim something.