[errcorrectcode]

The timeline seems like an unknowable due to the nature of technological progress: discontinuous jumps that usually require discover manufacturing techniques in secret.

Not as a UFO or conspiracy theory, but as a realization that there are some technologies intentionally kept secret to maintain military, political, or economic advantages.

When that distance between in-the-pipeline reaches a magnitude delta of 2, then I'd be concerned about what's already being designed or kept in secret.

Scaling QC is a difficult, unsolved problem of manufacturing.