I think it can survive. The blockchain may not be known that much without bitcoin but because there are altcoins it may, depending on how these coins are promoted or used. If they cannot create more market for these coins then the blockchain will be a hollow block empty and void. The blockchain technology can live without cryptocurrency. I think that nothing will change radically If all supporting computers and users will receive Fiat for using the computing power of their computer. it has other features that can operate on it aside from Bitcoin.