Quite true which is why it isn't advisable to take your investment decision basing on coins from the said top position (example; top 10/20 etc) as many people do. Looking at suggestions whenever some noobs comes to seek for help, you'll see people giving suggestions of selecting coins from top somewhere without realizing that this coins aren't constant and many times this are high ranked users giving this advice.
They forget that this coins get to the top mostly because of the pumps then slowing loses that position when another shitcoin gets pumped. For example in the last 2/3 years we had coins like EOS in the top 10 but today it's no more instead we now have hyped projects like Solana and others dominating.
I'm not trying to downgrade all projects there but do know even though a project is quite genuine, due to how the altcoins market is stationed, they get hyped and overpriced for no good reason. Just people fomoing and given their Bitcoin always in exchange for tokens that would fade soon.