I think they have possibility but only few coin have chances to overtake the bitcoin, but now ethereum is one of the coin who I see are qualified for that.
Bitcoin will still king after few years but we do not sure the value of it because remember the price of the bitcoin is volatile and unpredictable so many people are didn't know what would be the next movement for this coin but now will celebrate the of what bitcoin already achieve..
Not only the king, but there's also no smart guy who can create a coin that the same as the bitcoin, it's a purely decentralized coin and has a fixed amount. That is the reason why most coins did not beat bitcoin, decentralization plus factor is being an anonymous transaction. That's the beauty of bitcoin that every dev team trying to understand and copy the protocol code of bitcoin.
Tell me which coins have the same feature as bitcoin and that will I guess will replace bitcoin.