Tenson, I suspect what you're saying is essentially true. But speaking for myself, I'm prepared to accept the possibility that there are things that we can't measure (or at least, that it hasn't ocurred to us to measure) which may affect the perceived sound.

My hunch is that psychology is the main factor at play when it comes to cables -

or

There's a way to eliminate this factor - a double-blind test - but for some reason this seems to be a bit of a taboo amongst many hi-fi types ... I'm not sure exactly why. Perhaps because it would spoil the "magic", perhaps because it wouldn't be terribly helpful to certain retailers' sales figures.

We can argue all day about possible scientific explanations - but as many have pointed out, it's whether (not why) it actually sounds better that matters. And it seems to me that if there was the will, this could be quite easily determined once and for all.