Encryption and Quantum Computing

We have all seen in the news lately arguments for and against encryption with governments trying to ban encryption and making it so that companies producing hardware must have a back door for a government agency to have access if it is required.

What is the state of affairs when quantum computing is further developed and refined then applied to encryption? I would assume that the costs involved in quantum computing would limit the availability to government agencies, military and commercial entities. Would quantum computing essentially make encryption laws and protection redundant?

I don't know. Depends on how powerful the supercomputers are. The major purpose of encryption today is (I think) to provide a safe connection between peers and prevent bulk mass surveillance.

Let's say there is a very powerful supercomputer that can be used to break an encryption key (something commonly used, like AES-128-CBC) in a week.

A very powerful quantum computer to replace it can maybe do the same in an hour. That is 148x improvement, however considering there are a few billions of people on the Internet, it still means that the entity in ownership will have to decide which communication gets decrypted.