I spent my professional life measuring consumers'/users' subjective experience of products using various psychometric techniques. I always sought to obtain objective metrics from engineers and designers as well and then correlated those metrics with perceptual measures using multivariate statistics. This reveals both what differences are perceived and, also, what physical product features are correlated with those differences.
Differences among cables, or any other audio component, can be resolved objectively in this way. I actually did research like this with automotive audio systems back in the day. When questions such as the present one come up I always wonder why this type of research isn't done more often in audio.
