How can these coins would replace bitcoin? Are you sure that these altcoins can fairly overtake bitcoin? I'm thinking of it before but the closest one few years ago was Litecoin but we all know what happened to its boat so its not the closest one anymore.

And regards to these suggestions that can potentially overtake bitcoin, I don't have any choice for these coin. I have Ethereum but I still don't think that its old enough and worthy to overtake bitcoin, well why we have been thinking about this?