He’s right that current quantum computers are physics experiments, not actual computers, and that people concentrate too much on exotic threats, but he goes a bit off the rails after that.

Current post quantum crypto work is a hedge, because no-one who might face actual physical or financial or military risks is prepared to say that there will be no device in 10-20 years time that can crack eg. an ECDH key exchange in the blink of an eye. You’ve got to start work on PQC now, because you want to be able subject it to a lot of classical cryptanalysis work because quantum-resistant is no good by itself (see also, SIKE which turned out to be trivially crackable).

The attempt to project factorising capabilities of future quantum computers is pretty stupid because there’s too little data to work with, so the capabilities and limitations of future devices can’t usefully be guessed at yet. Personally, I’d expect them to remain physics experiments for at least another 5-10 years, but once a bunch of current issues are resolved you’ll see rapid growth in practical devices by which time it is a bit late to start casting around for replacement crypto systems.