Sure, but breakthroughs are unpredictable by nature. And we can't even prove mathematically that our cryptography is secure against classical computers or a guy with a pen and some paper.

Generally agreed, but look at the progress of quantum computers:
In 2001 the number 15 was factored with Shor's algorithm on a quantum computer.
In 2012 Shor's algorithm was applied on a quantum computer to factor 21.
And now it is the year 2025 and we are still on 21.
In practical cryptography we use numbers that are about quattuorvigintillion times larger.

Filiprogrammer

bitcoin

How hard will it be to reach consensus about a quantum upgrade ?

stack_harder

Lot's of tech is impractical until, with R&D, it becomes practical