Google has already claimed that they achieved quantum supremacy. It's a revolutionary in the computing world. I think that through it could help boost the computing power of the blockchain to produce much bitcoins than our present computers.
Quantum computing with regards to blockchain technology is a much more deeper topic than just faster mining of bitcoins. The main concern isn't faster generation of blocks, but rather the security impacts to blockchain because of exponentially faster computing speed that a quantum computer can do versus traditional, and even supercomputers. Even though it's faster, quantum-proof algorithms and methodologies to further secure our sensitive data, whether on network-side of things or hash/cryptography aspect, is already under development.