I believe that there will be another cryptocurrency that will exist.  I believe in the saying, that what is bound to happen will happen.  If you look at the history of cryptocurrency, Bitcoin isn't the first one to be created but Bitcoin became popular because of the idea of a decentralized blockchain.  Bitcoin is powered by blockchain so basically, if Bitcoin does not exist, others will take the Bitcoin slot because of the existence of blockchain.

But if blockchain does not exist I believe Bitcoin as decentralized blockchain won't also exist.