Basically, Bitcoin was created to simplify the P2P digital payment system, then we saw Bitcoin having some shortcomings such as a limited amount of Bitcoin and speed problems, then the altcoins came to perfect the system that Satoshi Nakamoto hoped for, then we saw there were a lot of altcoins and Until recently, new projects are being developed, it's not a matter of winning or losing, all systems need updating and that's why I would think if Bitcoin didn't exist then would altcoins exist? of course not, because they were all ideas and those ideas resulted in lots of altcoins that everyone can use today