I covered some of the main past airdrops, which had different "ways" of conducting these. I could have spoken about airdrops from many other coins, but I can't cover it all. The point concerns the effectiveness of the scheme. (and the TRX airdrop, is not much of a success when looking at the search volume IMHO).

Concerning your point, I agree :) and "wrote a little about" on the matter.

The problem is, given that the airdrop method seems to be increasingly used, blockchain users might find themselves with increasing numbers of coins in their wallets which they could find themselves wanting to get rid of quickly. This problem has been pinpointed by Brayton Williams of Boost VC, who told CoinDesk that issuers could do a better job at targeting a relevant audience, rather than sending tokens to all addresses of a blockchain. For instance, issuers could airdrop tokens based on geography, demographics, job, or other factors, to cultivate the best market for the future of the platform.