I think that airdrops is a temporary phenomenon, because most airdrops eventually do not pay, and sooner or later people will finally be disappointed in them and they will disappear.
Yeah, sometime airdrops are disappointing for many people who join in the project. Maybe it will be better if the people (who are just joining the airdrops program before) try to invest in another project (which is not free), maybe it will give more profit (don't forget to analyze the project first) than before.