Majority of those coins on top 20 are old coins and few are new ones with different network or chain. This year is the surge of defi's and nft's the new trend that is why new coins comes from these kind of projects. Bnb made it to the top 4 and also polkadot has shown good performance at top 6.
Yes, and really agree with what you are saying, but I am also still surprised by some people who still like new coins and forget about old coins that already have tremendous potential and volume at this point.