I don't think like that, Bitcoin is the center of crypto currencies and altcoins are complementary.
Bitcoin and Altcoin have different roles, therefore they complement each other rather than destroy each other.
They are not helping each other, the same thing that they competing in the market and to find out who gonna be win the race. If they have potentials, then it have to believe that they could make it but somehow, bot all of them don't have.
Bitcoin is very promising than of altcoins that is why investors give more investment in this coin than of altcoins and so it always been on the top among others.
altcoins compete with each other for investors not familiar with the project, and at the same time really complement each other, in working on the same exchanges than it is profitable to trade and than to move funds between exchanges.