From my own experience I can tell from all the airdrops that I know the top projects were only: Vite, Ontlogy, Dfinity. All others were shitcoins

Sad to say but, yes it is true that 99% of airdrop is either scam or shitcoin. It is because there is no regulation in creating a new ICO. It is also easy to create a new coin from different platform like Ethereum platform and Waves platform and today there are new platform that is available in the market that is why expect more shitcoin by next year.