Recently, I was thinkig. Is there really any reason for the BTC to be the market leader? The only thing that is giving the value to BTC is pretty much the fact, that it was the first crypto currency. It is the grandfather of all cryptos. But we know it has its flaws... It was never designed for broad usage, it has scaling issues and so on.
I don't think that this is a correct formulation of the question, these two cryptocurrencies completely different. Perhaps bitcoin wouldn't grow as an ether, but it will always have the glory of the first and most importantly decentralized cryptocurrency. Moreover, the growth of the ether is supported by ICO.