From my limited understanding, that's actually the opposite of the truth.

In QC systems, the engineering "difficulty" scales very badly with the number of gates or steps of the algorithm.

Its not like addition where you can repeat a process in parallel and bam-ALU. From what I understand as a layperson, the size of the inputs is absolutely part of the scaling.

The fact that it does appear to be so difficult to scale things up would suggest that the argument isn't silly.

Actually yes, how much numbers you can crunch per second and how big they are were among the first benchmarks for actual computers. Also, these prototypes were almost always immediately useful. (Think of the computer that cracked Enigma).

In comparison, there is no realistic path forward for scaling quantum computers. Anyone serious that is not trying to sell you QC will tell you that quantum systems become exponentially less stable the bigger they are and the longer they live. That is a fundamental physical truth. And since they're still struggling to do anything at all with a quantum computer, don't get your hopes up too much.

NSA is pushing for PQ algos.

So in my view, the issues I think about now are:

- Too few researchers, as in my area of quantum computing. I would state there is one other group that has any academic rigour, and is actually making significant and important progress. The two other groups are using non reproducible results for credit and funding for private companies. You have FAANG style companies also doing research, and the research that comes out still is clearly for funding. It doesn't stand up under scrutiny of method (there usually isn't one although that will soon change as I am in the process of producing a recipe to get to the point we are currently at which is as far as anyone is at) and repeatability.

- Too little progress. Now this is due to the research focus being spread too thin. We have currently the classic digital (qubit) vs analogue (photonic) quantum computing fight, and even within each we have such broad variations of where to focus. Therefore each category is still really just at the start as we are going in so many different directions. We aren't pooling our resources and trying to make progress together. This is also where a lack of openness regarding results and methods harms us. Likewise a lack of automation. Most significant research is done by human hand, which means building on it at a different research facility often requires learning off the person who developed the method in person if possible or at worse, just developing a method again which is a waste of time. If we don't see the results, the funding won't be there. Obviously classical computing eventually found a use case and then it became useful for the public but I fear we may not get to that stage as we may take too long.

As an aside, we may also get to the stage whereby, it is useful but only in a military/security setting. I have worked on a security project (I was not bound by any NDA surprisingly but I'm still wary) featuring a quantum setup, that could of sorts be comparable to a single board computer (say of an ESP32), although much larger. There is some value to it, and that particular project could be implemented into security right now (I do not believe it has or will, I believe it was viability) and isn't that far off. But that particular project has no other uses, outside of the military/security.

I'm not going to pretend that I am that knowledgeable on classic computing history from that time period. I was primarily going off the fact the semi conductor was built in the late 40's, and I would say we have the quantum version of that in both qubit and photonic based computing and they work and we have been developing on them for some time now. The key difference is that there are many more steps to get to the stage of making them useful. A transistor becamse useful extremely quickly and well in Quantum computing, these just haven't quite yet.

There is private sector adoption and planning now of specific single purpose focused quantum devices in military and security settings. They work and exist although I do not believe they are installed. I may be wrong on the exact date, as my classical computer knowledge isn't spot on. The point I was trying to make was that we have all the bits we need. We have the ability to make the photonic quantum version (which spoiler alert is where the focus needs to move to over the qubit method of quantum computing) of a transistor, so we have hit the 50's at least. The fundamentals at this point won't change. What will change is how they are put together and how they are made durable.

Aaronson says:

> This is the clearest warning that I can offer in public right now about the urgency of migrating to post-quantum cryptosystems...

That has a clear implication that he knows something that he doesn't want to say publically