No doubt that there is no other cryptocurrency or altcoin that can supersede the bitcoin. At least not for the next 5-10 years. Of course there are many rising competitors like Ethereum, ripple and litecoin.
Do you agree???
Ripple is centralized so it absolutely cannot replace Bitcoin
Litecoin is a little brother of bitcoin and also cannot replace bitcoin
Ethereum was not born to the same purpose as bitcoin => will not replace bitcoin.
I think bitcoin is good enough except scaling problem. The DEV team is working on it to find solutions, Lightning network is an example.