There is no way of XRP to replace the Bitcoin (BTC), bitcoin will always be the at the top of the cryptomarket, Ripple (XRP) is not fully decentralized, while bitcoin is fully decentralized. Ripple will be mainly use with the bank transaction while bitcoin is for an all around transaction.
Bitcoin is holding money where as Ripple is trying to resolve the problem of bank transfers worldwide. They both have a different scope and work differently and are doing different things so in my view cannot be compared.