there is no way a power cord that is connecting hundreds of feet of regular blah blah yada yada
The last 3-6 feet of conductors in the power line are the most important. I've also seen blah blah blah yada yada
These two quotes are two sides of the same coin. Which turns out to be a wooden nickel. The first 3 to 6 feet from the panel matters just as much as the last 3 to 6 to the component. Also the wire 30 to 60 feet BEFORE the panel matters just as much as those last few feet. Improvements made ANYWHERE along the way- or before (or after!) are equally noticeable regardless of whether its continuous or in sections. Every single foot matters.
This by the way is not guesswork, conjecture, or repeating blather others spouted once upon a time. This is from crawling around under the house treating wires, taking a panel apart (yes, down to the bus bars) and treating everything, even doing something clear out at the meter. Makes no difference where, its all equally good, in fact the changes made in the panel far away from the system are if anything better in magnitude than "the last 3-6 feet".
This ain't no placebo either. You do one, maybe you can convince yourself. But you do as many as I've done it adds up to something so extraordinary audiophiles are driving 200 miles and saying its fantastic and the best they ever heard, and that simply does not happen from no freaking placebo effect. Just don't work that way. Sorry, but you'll have to cook up some other equally nonsensical story masquerading as science.