Bitcoin is the big dog in this market. Being the original cryptocurrency + being the one receiving mass media attention + people being fascinated with its growth over the years, has basically put it in the position of being the anchor of this entire market.

Sure, there may be other coins out there with better technology which, in theory, are superior, but the reality of the market at the moment is that when bitcoin tanks in price, pretty much everything else goes down with it - most even go down further than that because they can only be bought with bitcoin and their value in satoshis decreases on top of the dollar decrease of bitcoin.

Because of this, I can't see anything "overtaking" bitcoin with the current state of the market. That doesn't mean altcoins can't have higher % increases over a period of time though - it happens quite a lot.