Dan, thanks for taking the time to explain.
Sorry, but I've been too busy to respond in a timely way.
I started with 14 gauge stranded copper in my system many years ago. When I began upgrading I replaced it with Kimber 4TC. I don't recall exactly, but it was over $1.00 per foot, which I thought was expensive badk then. Over time, I found that I wasn't happy with the way it sounded, and dragged out my old stranded copper to compare. I really couldn't hear a difference, but my listening skills were less honed than now. Yes, I believe that as you gain experience, you develop better listening skills.
A year or so later, I made a big upgrade purchase and switched from the Kimber to Audioquest Midnight. This was about $300 for 10' at the time. The improvement was not subtle. At that time my wife was a little more involved in what I was doing, partially because she was trying to figure out how much I was spending on this stuff,

, but she immediately heard the difference from the kitchen upstairs. She didn't even know what I had done, but exclaimed that it was sounding pretty good.
Since then, I have periodically pursued upgrades, including speaker wire; some very, very expensive. There has not been a direct correspondence between price and performance, but there have been noticeable audible differences. In the end, I have settled on a product that has yielded the best results I have heard so far, and at a price that is far lower than others I've tried, but at the same far more expensive than 6 or 12 gauge copper.
Do you dismiss off hand the improvements that might be derived ffrom things such as better quality copper or silver because of the process used in its extruding, such as the elimination of oxygen, or in the architecture that is used in the speaker cable's design such as a helix or single strand vs multi strand, or in the use of a signal ground, or the type of dielectric used, or spacing between wire, or the type of shielding and whether there might be an interaction between the wire and the shielding? It seems to me that there are many factors that can enter into the design of a speaker cable, and whether or not these factors are audible can be verifiable.
I know that differences in design can effect bass, treble extension, brightness, transparency, soundstaging, image smearing, detail retrieval, etc. I do believe that a good 6 or 12 gauge wire can provide a good balance of all of the above components of sound, and along with it your best bang for the buck, but I do not believe that it can elevate your system to higher levels that a well designed wire can.