Although nowadays it's not that much worth participating in airdrops and bounties, people like me still do it because we do not have choice and this can be done part-time.
Jobs you mentioned need technical background or knowledge. Many bounty hunter do not have that but are good in social media marketing.
I agree, also not all participants has an ability to be developer or what. some people here are contented to participate in campaigns as a part time, maybe some of them are here to read and to learn more about cryptocurrency so that maybe in the future they have a possibility to become a developer or to be a team manager.