Well no one knows what it would be on the future, but I doubt that there will be a coin to beat bitcoin. As of now I don't see a coin which has a potential to overcome bitcoin. Well I would say that other coins like Ethereum, EOS and NEO could compete with bitcoin, but still bitcoin would be the number one on cryptocurrency. Especially bitcoin has the highest price of all, I think bitcoin would be the great leader of all the altcoins. Still, for me there will be no one to be able to surpass bitcoin, if ever there will be then it would be really too long for it.