I think it's high time projects know that they cannot rely solely on bounty and airdrop as a means of promotion. A lot of projects launch and they rely on their bounty campaigns and airdrop to help bring in investors and therefore fail to reach their softcap.
I never said bounties are not effective but it should only be used to create and reward their community not to bring in investors. If a project wants to promote it crowdsale then the team should deploy real promotional means like paying top influencers, attending conferences, advertisements on top sites like coinmarketcap, etc. Because no matter how good the project is, if it can't market properly then it won't reach its goals and if a project is mediocre but have a top notch marketing program, it will succeed beyond expectations.
I agree with your point of view, all of which are very reasonable. But it is only suitable for projects that have invested initially or are backed by big VCs, because as you say, hiring celebrities, participating in events is very expensive.
With startups, they don't have enough money to do that, so bounty is still an effective way when they pay with their own money (tokens), and promoters will have money if the project mobilizes funds.