actually you are right, because that was once a method to promote cryptocurrency especially Bitcoin and as of that time many of the AirDrop survived but recently I don't think that there are people who make such kind of profit from air drop any longer, another thing is that we should not overlooked it because some people may be profiting on it right now but based on we don't have interest or so many persons does not have interest on it then may think that there is nothing on it, probably maybe people who is into it as I said may be having a profit while the are into it right till now
The early participants that involved themselves in airdrops and bounty made huge amounts of money from so many airdrops but what we are seeing these days is the opposite of what participants supposed to be getting from crypto airdrops.
Many projects that are launching Airdrops now are very greedy and they don't even want to reward their community in a way that everybody would benefit after so many tasks given to them to accomplish in the limited shortest time.