Before I got into the "high end" Hirsh Houck of Stereo Review was my Guru, and he couldn't tell the difference between high quality amps, so I assumed there was little or no difference, but later on I discovered his hearing wasn't the best, although his answers to questions was as honest as the day is long. Those who can hear well know there are many subtle differences.
What is left out of the equation here, is how well we hear, as well as how well we listen. The differences between high quality "mid-fi" and legitimate "high-end" amps are both large and small. The price difference is usually huge, and justified as well due to more expensive parts, but can you "hear" the difference. Since those differences, such as "sound stage holography", depend on how well you hear, are not worth it to everyone, and a good Yamaha, might be as good as an "ARC" amp.
Awhile back I had a small hearing deficiency in my left ear; that's worse than an equal deficiency in both ears because you can never get the sound stage right. Now that my hearing has come back somewhat, I realize how subtle that sound stage thing is, especially when the left channel of my hearing comes in.
Whether or not high end audio is worth the cost depends on how well we hear; if you can not hear it, it ain't worth it.
Maybe everyone should have the blindfold test before they buy.