i don't think they kill the project. the bounties and airdrops help the project a lot. imagine that the project without the bounties, the world won't know about the project. if the token/coins prices dump, i think it's because the projects run by some amateurs team member. the projects will die if the team abandoned their project and do not create the product properly.
it doesn't kill the project, but on the contrary, it can even help a project grow. There are a lot of things that make them think that because once the bounty and airdrop have been distributed, the prices suddenly dump. even though this can be prevented by paying participants using stable coins. other than that, only weak projects were damaged by the programs they created themselves.