Quick story,

I’ve been involved in speaker upgrades for many years. After retirement as an audio dealer, my tech of 25 years and I work one day a week trying to keep good, but broken hifi gear from going into the dumpster. We also offer performanace upgrades. I’ve discovered that power delivery matters, and began the practice of installing "better stuff" in vintage gear. Begin at the wall outlet, we take the high voltage upgrades internally, improving anything in the high voltage power path. We’re pretty proud of our work, but are often surprised ourselves at the results. When we’re expecting noticeable improvements in "A", "B" and "C", and we get "A", "B", and "C" in spades, PLUS "D", "E" an "F" in good measure, I find myself unexpectedly glued the listening chair for an extended period of time taking in the new experience.

The two most accomplished and successful gentlemen in my orbit are my old college roommate, and a friend of 30+ years. When I spoke of my hobby, and some details related to what I was doing, my college roommate, a literal rocket scientist, shut me off abruptly with: "Nope!!! That doesn’t matter! You have to have atleast 50 feet of that cable to make a difference". I quickly changed the subject to something we agreed on: fast cars.

The other friend is an engineer who keeps vintage radio stations on the air. He’s also involved in the service and restoration of vintage broadcast gear -- open reel tape recorders, turntables, etc. One day I invited him over to my shop to listen to some "new" items I was feeling pretty good about. His reply: "That would be a total waste of time. Have you seen the power supply in my <popular amp brand>?!!"

So, here I was. A guy who merely tippy-toed into college physics, and after years of involvement, finally arrived at the esteemed position of being slightly smarter than the Radio Shack soldering station on my bench. I was faced with a near genius-level individual, and another who keeps classic rock stations playing in a 100-like radius of a major city. I had a confidence level of 90%+ in my findings, but had no superior technical track to pursue.

I still do what I do. My confidence level has nudged up to 95%. No regrets.

      I think your approach is very well written and very to the point you are seeking to make. If there is an answer to this issue it can be found in the same manner as would be used to determine whether chocolate ice cream is better or worse that vanilla ice cream.

     For the most part I think you are dealing with issues to which there is no or very little objective proof that one opinion is correct and one is not. In other words we all have opinions on things the correctness or truthfulness of which is not easily provable if provable at all. On the other hand, what fun would a horse race be if everyone knew who the winner was before the race and there was no judgment and betting involved before the race. There is always going to be differences of opinion and that is what drives people in selecting certain products over others, different cars over others, different speakers over others. \

     I think there are a least two variables here- one is the person's judgment that a system is too harsh or too laid back, etc. and the second is that person's  judgment that changing a cable or the position of speaker or effecting some vibration control etc. corrected the problem -based on that person's first judgment- that there was a problem that needed to be corrected.                                                                                             If it could all be objectively measured I think if wouldn't be nearly as interesting.

Audio is stuff a bite of everything on the table, add a sip and chew.  What would a sommelier recommend?  He/she might get ripped to shreds too.

@mceljo What conspiracy theories have you found in the wine world? Other than natural wine that is. 🤣

@jond  - "Conspiracy Theory" is probably too strong of a word.  I was just referring to the classic debate on how much the price of a given wine impacts the experience.  Can most people really tell the difference between different wines that cost orders of magnitude different?

I should test my brother-in-law sometime.  He and my sister actually named my niece after a favorite wine.  I could track down someone that could recommend the most similar inexpensive wine and see if I could get my sister to pour him a glass of it on the down low and see if he would recognize that something was off.