Is anyone willing to entertain the idea

that at minimum 50% of all differences audiophiles claim to hear aren't real?
If a Mac amp from 1965 is Stereophile class "A" today, then where are all the "improvements" that the Stereo Industry raves about each month. If each new version is "way better" than it's predecessor, how come something 40 years old is still state of the art today?
Sugden is another brands that comes to mind.
No dobut some differences are not real, mood and how much attention you are paying are under rated factors for most people. As a rule remove all 'tweeks' (including expensive cables) from you system once a year and add them back sequentialy as a test. Another question you have to ask yourself is what percentage of the differences audiophiles claim to hear are improvements? I have really gone through a few systems changes recently that while they got me listening since things clearly sounded different the changes were not 'better' after longer term listening.
I think the answer is obvious.
If you don't hear, or don't think you hear, any difference or improvement by adding/subtracting something in your system, then don't do it.

I never really have understood the apparent "need" that some people have, for one fellow to tell the other fellow what he can and cannot hear.

I certainly understand people making helpful suggestions about gear selection, based on what has worked for them in their applications. But to make statements about people being "psychologically duped" is a bit over the top, in my opinion.
Twl, I don't think the 'answer' is all that obvious. For example I would never tell you you didn't hear something you said you heard, but I wouldn't hesitate for a second to tell you that under similar circumstances I did not hear the same result as you describe. We might even discuss why we did or did not hear the same thing. The reader can then ask questions to determine the likelyhood of his hearing the differences or lack thereof.

But for the uninitiated who is looking for support I think it is fair to inform an inquirer of all of the possible reasons for a products raves when the technology of the product is mysterious or nonsensical (to many at least), including the possibility that the product and its promotion is intended to appeal to a specific, and dare I say because of inexperience, a more gullible, person trying to blindly improve their system.

I will always agree with the "try it, if it works for you use it" approach. Where I draw the line is when you have to BUY IT to try it with the hope that you can resell it if you can't hear a meaningful difference.

How about some "audiophile grade" Q-Tips?

No, I'm serious (not about the "audiophile grade" part ;~)) but I know from experience that ear care/hygiene is very important for optimum hearing/listening. Here are a couple of things I learned:

A mixture of half and half white vinegar and isopropyl alchohol. Dampen a Q-Tip and swab the inside of your ear canal (dont jamb it up against your eardrum!) This solution kills most fungi (great after swimming) and removes wax and oils. The vinegar is an antiseptic and the alcohol dries out any remaining moisture and stimulates blood flow.

Another one is ear massage. Grab your earlobe(s) and pull down as you gently move it forward and backward. This stretches the muscles of the inner ear and makes them more pliable increasing sensitivity. Then, grab the top edge of your ear a little bit toward the rear, and pull it straight up and then fold it down and forward over the rest of the ear and stretch lightly. Repeat a few times. It feels good and you'll hear better.

A free upgrade!!