Comparing quantum computing to time machines or faster-than-light travel is unfair.

I didn’t interpret the slides as an attack on quantum computing per se, but rather an attack on over-enthusiastic assertions of its near-future implications. If the likelihood of near-future QC breaking real-world cryptography is so extremely low, it’s IMO okay to make a point by comparing it to things which are (probably) impossible. It’s an exaggeration of course, and as you point out the analogy isn’t correct in that way, but I still think it makes a good point.

What I find insightful about the comparison is that it puts the finger on a particular brain worm of the tech world: the unshakeable belief that every technical development will grow exponentially in its capabilities. So as soon as the most basic version of something is possible, it is believed that the most advanced forms of it will follow soon after. I think this belief was created because it’s what actually happened with semiconductors, and of course the bold (in its day) prediction that was Moore’s law, and then later again, the growth of the internet.

And now this thinking is applied to everything all the time, including quantum computers (and, as I pointed to in my earlier post, AI), driven by hype, by FOMO, by the fear of “this time I don’t want to be among those who didn’t recognize it early”. But there is no inherent reason why a development should necessarily follow such a trajectory. That doesn’t mean of course that it’s impossible or won’t get there eventually, just that it may take much more time.

So in that line of thought, I think it’s ok to say “hey look everyone, we have very real actual problems in cryptography that need solving right now, and on the other hand here’s the actual state and development of QC which you’re all worrying about, but that stuff is so far away you might just as well worry about time machines, so please let’s focus more on the actual problems of today.” (that’s at least how I interpret the presentation).