Even so, I don't agree that quantum is a threat to crypto. There are already well known quantum-resistant encryption schemes being deployed live in browsers, today. Crypto can just start adopting one of these schemes today, and we're still probably decades away from a QC that can factor the kinds of primes that crypto security uses. The transition will be slightly more complex for proof of work schemes, since those typically have dedicated hardware - but other types of crypto coins can switch in months, most likely, if they decide to, at least by offering new wallet types or something.