It is good that new projects with new ideas enter the market and compete with the old projects.
All the altcoins were new coins some day ago like ETH or BNB and now are top coins.
It is normal part of the technology evolution that new ones replace some old ones.
The market is here to decide.
Well it's not really a guarantee that new crypto coins that are existing today will sureply replace those old ones. It will matter most on its own quality if it can compete with the old and trusted one. But it's also a great idea that new crypto coins have arise which simply means that the market is still able to generate new ones that are as competitive with the old and established ones.