Again, its all down to listening skills. For example, for years (1973 to roughly 1985 or so) I was absolutely convinced there's no way cables can make any difference. Not interconnects, not speaker cables. Certainly not power cords. Just no way!
Also back in the 80's firmly believed that if two CD players measure flat (which they all do) there's just no way there's any difference between them.
Sure enough, when I went at first and tried to compare I heard no difference. Later on, after many months of comparing different things, it was getting easier and easier to hear the differences. Not only hear them, but describe them.
All through the months trying to figure this out I would drag my wife to see if she was hearing what I'm hearing. Time and again she would say one sounds better. Better how? Just better. More expensive. Other one sounds cheap.
Bear in mind she had no idea which was which, or how much they cost (high end dealers tend not to use price tags much), or anything. All I did was say hey I think I hear a difference tell me if I'm crazy or not.
Only after we did this a bunch of times did we start talking about prices, is it worth it, etc. For a long time it was nothing more than can we hear any difference?
All during this time I was reading Robert Harley, trying to learn all these audiophile terms. At one point we were at Corner Audio in Portland and the old guy says hey try these things, which were expensive little squares with some carbon fiber you put under the speakers. Sure enough, wow, greater clarity, better detail, improved dynamics. Timbre improved, ie each instrument sounds more like what it is. Imaging was more focused, both L to R and front to back. From these stupid little squares.
My wife heard the same thing. She just didn't have the words to express it. Lacking the words brings doubt, since we just don't seem very able to know what we know until we have the words to say what we know. Sorry, but that's just the way it is. I've since learned there's a branch of psychology that questions whether we even have the capacity to know something without knowing the word for it. Which opens up a whole chicken or the egg thing. We report. You decide.
Anyway, bottom line, its beyond settled that these differences exist, that some things sound better than others, and that we can hear and choose and evaluate.
Once we develop the necessary listening skills- and lingo. They go hand in hand.