Yes it could be possible,right now there are too many cryptocurrency that makes its appearance to the bitcoin world.There is an a!tcoin that is threatening bitcoin, even if that coin is very young or that coin is just starting I think it can be really a big problem to the bitcoin.Aside from the ethereum's rapid growth the altcoin helps too many people also,so that is some proof that it can replace bitcoin.But from now it's bitcoin that is the general coin that is used,so no one can ever predict.
Of course this can be possible as we know about altcoin is that altcoin is becoming popular in the market and people started investing in altcoin instead of bitcoin because altcoin show to the people a new project and we know people love the change and I am sacred about bitcoin now because if that happened continuously then price of bitcoin will goes down very quickly.