If the gullible with deep pockets are assured of promised improvements by slick marketing campaigns well let them spend thousands on a power cable that might possibly make a whopping 1/2% improvement.
Have you ever heard top gear and what that, even the small percentage you are referring, is capable off.
Even with that, it would be interesting to know the science behind how that last 6 feet of cord overcomes all the ’ sound’ from the 100 feet of crappy Romex.
Why should not be the first six feet?
The ’size’ or the thickness does not mean a thing (in this case) At the present, I am using AN Kondo power cord in my tube preamp that has the smallest diameter of all I have tried, but it gives me the sensation of the deepest stage, like no other has.
True, especially for Kondo where there is magic in all of his cables (and not only).