The same thing happened to me too... When I first joined the airdrops I received almost all of them, and that happened even being a Newbie on Bitcointalk. Now, as a Jr. Member I`m receiving less airdrops. And most of the airdrops are not classic "fill the form" airdrops, they are some kind of bounty - they require more tasks to do (join the telegram, follow twitter, retweet, even register on other forums and post there for a while)

So, I guess now there are many fake/ scam airdrops, that`s the only explanation.