Ripple overtake Bitcoin? Wow, that would be a tragedy, and would go against everything that the cryptoworld stands for, which is mainly a decentralized monetary system. Remember that Ripple has an unlimited supply as well...kind of like fiat.
I do not believe there will be any coin that can replace bitcoin and the ripple too. Although Bitcoin is having a lot of bad news, bitcoin still has a lot of good features that other altcoins have not. So I think bitcoin will still grow very well in the near future, this year bitcoin target is 100k USD, I think this is possible to do.