You are likely to need quantum computers to demonstrate that they can feasibly break encryption in order to get people to switch to post-quantum cryptography.
The fact that an algorithm exists for a non-existent computer system does not meet that bar. Conventional computers can also break encryption given enough speed and power - it's just not yet feasible as with quantum computers.
The fact that an algorithm exists for a non-existent computer system does not meet that bar. Conventional computers can also break encryption given enough speed and power - it's just not yet feasible as with quantum computers.