Don't get me wrong Chris, I take no issue with your statement that you have never heard a difference and I agree with most of your statements regarding quality. However I have heard a difference in my system.
If nothing else, you are in good company.
If you read a copy of Audiophile, or attend a high-end show you will find many who will agree with you.
Personally, I have never heard a difference once a somewhat basic minimum standard is reached on a 3 foot interconnect.
To my knowledge, no one has delivered a spectrograph, waveform, or other piece of concrete physical evidence to show that any cable can deliver on the promises many make.
I have read metallurgical analysis, electromagnetic analysis, etc. of many brands with special shapes and kinds of wire and none seem to deliver a measurable end-result.
We are able to slice and dice an audio-level signal with great precision these days.
"Seeing" what we hear isn't a futuristic science, it has been done for decades, with improvements all along the way.
If spending a week in the lab could demonstrate that an interconnect is worth $1000, I'm sure that we would not have to look to hard to find that report.
I am reasonably sure that the "magic" cable doesn't exist, but always keep an open mind.
If you are anywhere near NYC, I'll take you up on the interconnect challenge.
I have a trip to two showrooms, on in Manhattan, and the other in Philly to listen a bit deeper.
Both have salesmen who absolutely insist that I will hear the difference.
While I doubt that I will hear anything, the showrooms will be a great way to spend a rainy day!