I do not think Bitcoin needs altcoins. Each altcoin brings different innovations. But as a payment system, Bitcoin already meets our needs.
Even if there is no altcoin, bitcoin will continue to exist in the population.
I think bitcoin also need altcoin to foster price. Well, to buy altcoin, or distribute bitcoin, sometimes it takes a bitcoin, so, people need to form altcoin bitcoin, and bitcoin it makes the price to rise. Well, now very much a project and of course it affects the price of bitcoin.
People value the value of something. Even if there are no altcoins, people can claim bitcoin. As people buy bitcoin, the price will already increase. There is no need for altcoins for this.