Airdrops not totally reliable, talking of airdrops then was 2017 and 2018 there were many project that was only launching airdrop and got succeeded without running any other marketing or further promotions but after few years back scammers invalided using airdrops and some phishing  site swipe people make it difficult to people to join airdrop. Secondly due to large numbers of participants joining airdrop at last it turns to trash payment.