I will offer my honest opinion, which has not changed by registering on this forum. I don't think bitcoin needs altcoins, I think it's more the other way around. What I do believe is that in the future some altcoins will coexist with bitcoin, but only a tiny number of the tens of thousands that exist now.
Having a decentralised, autonomous, tremendously secure system (or currency, if you prefer) that is very difficult to censor and confiscate, there is little more need for it. And with the implementation of CBDCs there will be even less room for altcoins, I think.