But I will not agree with OP that we shouldn't assume that the project we join will not successful since if that's the case I will not any of those since we are wasting our time and for sure the reason why people join in certain bounties since they believe that they will became successful and earn with them.
I don't mean all the bounty hunter joining a project will not successful. Like I said, there are 2 way to become success project, by marketing and promoting. If promotion from bounty hunter doesn't attract investors to invest in their project, they still have a marketing strategy. Both team and developer should work very hard to make the project is interesting, unique, have good convincing skills etc to attract the investor.