Is it? I've generally understood that most symmetric cryptography like AES is safe. QC only gives exponential speedups on some specific problems. The most is that naively you might want to double your keysize to get the same protection, something that the article points out is unecessary because that naive approach assumes that QC is like classical computing but with extra magic, as opposed to having its own tradeoffs.

Is it possible you are confusing AES with RSA?

I've heard a lot about Shor's algorithm breaking RSA, but this article on hackernews is the first I've heard anyone discuss quantum attacks for AES. Then again, I am in quantum computing not cryptography, maybe different circles have different discussions.

Because some people make their living from the vague possibly it might work one day. It's the cold fusion of computing.