It's written so many times here that whenever bitcoin goes green all the market goes green and the same hold true for red bitcoin also.
I don't think any coin is going to come out and overtake the number 1 position that Bitcoin holds anytime soon. Ethereum has had a good run, but it's market cap is still only 1/10th of Bitcoins. I think Bitcoin will always remain on top. It's basically a requirement to buy Bitcoin before you can buy any of the other altcoins as it is right now. So unless that changes and you can buy said altcoin directly easily, Bitcoin will stay on top. Everytime you invest in an altcoin, it raises the price of Bitcoin slightly since you have to have it first to trade for an altcoin usually.