There are many reasons why altcoins exist and the main reason is that anyone can create one in a permissionless fashion. Other people have created altcoins to compete with bitcoin and the projects claim to offer better privacy, more decentralization, or they focus on something that bitcoin cannot do.
Then there are those that have a utility function. Personally, I appreciate coins with utilities that's why I love the ARCADE platform where hodlers of $ARCADE are allowed to earn meaningful rewards, from various Play-to-Earn metaverse games, without requiring gameplay or even NFT ownership.
So, I believe many more altcoins will still be launched and get the crypto space better.