No, not always. Most of airdrops are just scams. Some of them are sending even coins, but those are just shit-coins. However there are really good airdrops also. It is really difficult to find out such a nice projects. Experience and doing own research will help to find out such a good projects.
I totally agree with you. Now a large number of airdrops pass every day. But only a few give real money. Most do not even send tokens. Some airdrop send tokens that are absolutely useless crap. And only a small part of tokens from airdrops will cost real money.