"...justify an improvement in sound over a $1K cable..."
At that point, diminishing returns have been in action for more hundreds of dollars than you could count on one hand.
Anyone (everyone) care to throw a dart?
I understand my hearing at 69 isn't even close to what it was at 19. I'm sure your results may vary. However, anyone care to throw a dart at the price point where diminishing return kicks in? There must be one out there. Regards, AB