dude's alleging secret future-tech developed by some modern covert bletchley park, and you're gonna refute it with a fine point about what algorithms can currently do? I don't think you two are playing tennis on the same court.
I still found the exchange, informative/insightful and apropos.
My point was that "quantum computer" sounds like a scary apocalypse scenario, but isn't. It makes key exchange awkward but by no means impossible.
We already know that GCHQ has an underground level full of conventional computers. That's a lot scarier.
Well it would reduce the security factor of AES-128 to as low as 64bits which is somewhat tractable.