Most audiophiles do have nice systems, because they have spent a great deal of money on them. Much more than necessary, typically.
The phenomenon has been around since the advent of "hi-fi" in the 60's, when there was a big boost in quality, fueled by widespread interest in stereo. Stereo went from being a curiosity to universal acceptance over the course of that decade. I still remember the first stereo recording I ever heard played on a stereo. It was Magical Mystery Tour. I immediately realized that there was stuff going on in recordings that I hadn't been hearing before, and set about to determine what else was in there that I'd been missing. I found out that there were low frequencies in there that I hadn't heard before, because my speakers were too small. So I got bigger speakers. Then I found out that you need the right kind of speaker enclosure to get those lows. And on and on.
At some point my sound system got good enough that I could hear things like harmonic distortion. Sure enough, an amplifer with 1% THD sounded better than one with 3% THD. But there are diminishing returns. An amplifier with 0.1% THD does not sound different from one with 0.5% THD. Event with 5 times the distortion, the latter is still below the threshhold of perception with anything other than a test tone.
But nobody wants to admit they can't hear the difference, although they fear that someone else can, and will scoff at their high-fidelity system. So the simple solution is to buy very expensive components with great specs. Then you're covered, even if you can't actually hear the difference yourself. Or if, in fact there is any difference at all.
We tend to associate high prices with high quality, even though common sense says that's not always true. Marketers have discovered that if you charge a high price, consumers will presume a high level of quality. If they lack the means to objectively verify that assumption, the lie escapes discovery.
Now the most curious aspect of all this is that people will swear they really can hear subtle differences. I suspect that many are not lying about it, but genuinely believe they hear a difference. And once you've subjectively heard or seen something with your own senses, no amount of objective measurement will dissuade you from believing what you heard or saw.
Try this experiment. Sit somebody down in front of your stereo and play a few seconds of music. Then tell them that you've noticed that the stereo sounds better after it's warmed up. Leave the room for 10 minutes, then come back and play the same music. Ask your subject if he or she can hear the difference. (Note: you're not asking if there IS a difference, only if they can HEAR the difference. The presumption is that there is a difference)
Nearly every time, the subject will hear a difference. Why? Who knows? Maybe they're not sitting in exactly the same position as previously. Whatever the reason, they DO hear a difference.
High-end cable makers love to cite A/B tests to validate their claims. But it's the same scenario. Tell the listener the fancy cables will sound better, and they will.
But no cable manufacturer actually submits to double-blind tests! If they did, they'd find that listeners randomly choose A or B as sounding better.
Umm, I'm rambling again. Is it 5:00 yet?