When this idea of ICOs started, people participated, both the rich and the poor took part until some projects turned into scam ones which has since then frightened people from investing in a project. Listing on the major exchanges also requires some amount of money which when the ICO did not end successfully, it will be hard to pay for. This is one major reason why icos turn scam and run with the little contributions they get instead of using it to list their shit tokens on an exchange. Bounties are successful when an ICO is successful so we do not have to talk more about that.