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.