There are few Quantum computers in "production" . If they have a solution to the superposition problem - it will be the end of cryptography as we know it. Of course I think that cryptogpraphy will evolve as Quantum computers emerge.
On the Jamie Dimon part, I would like to say that he was against bitcoin, but he always said that Blockchain is here to stay.
Technology is evolving so rapidly that the block-chain is just the tip of the iceberg lol. In five years block-chain will be the least of our interests, bold statement but its about to get crazy in the tech world.
do you have anything perticular in mind ?