Your analysis is correct, in that if there are any audible consequences resulting from having unequal lengths, they would not be due to the infinitesimal difference in arrival time that would result at the listener's ears.
However if other parameters, such as resistance, inductance, capacitance, and possibly skin effect, are not small enough to be negligible in the longer cable (all of those effects being proportional to length) a length disparity could conceivably have audible consequences.
Whether those consequences would result in sound quality that is better or worse than if the shorter cable were lengthened to equal the length of the longer one is speculative, IMO, and most likely system and listener dependent.
For further discussion see this thread.
Regards,
-- Al
However if other parameters, such as resistance, inductance, capacitance, and possibly skin effect, are not small enough to be negligible in the longer cable (all of those effects being proportional to length) a length disparity could conceivably have audible consequences.
Whether those consequences would result in sound quality that is better or worse than if the shorter cable were lengthened to equal the length of the longer one is speculative, IMO, and most likely system and listener dependent.
For further discussion see this thread.
Regards,
-- Al