Order of magnitude increase =/= unlimited, right? Also, it's my understanding that there is already plenty of work done on post-quantum cryptography. I don't

Order of magnitude increase =/= unlimited, right? Also, it's my understanding that there is already plenty of work done on post-quantum cryptography. I don't know if it's entirely a solved problem, but my understanding is that it's at least solvable. Perhaps someone with more domain experience can weigh in.