Nice post, BR! You are clearly correct that speaker cable cannot add to the signal (unless it'[s picking up signals extraneous to the source signal). I also agree that barometric pressure and other environmental factors probably contribute more to the SQ (or detract from it) than interconnects or speaker wire. I also think that spending a lot of money on cable is unnecessary.
All that having been said, I really like the Mapleshade wires and ICs. JMO. Of course, I also like Axiom speakers (terrific value for the money) and the Sonic Impact T-Amp (outrageous value for the money) tube amps, persimmon woods, Titleist tour blades, balata 90 compression balls (if you can find any anymore) and manual transmissions (hence the user name).
Enjoy the Music. Trust your ears. Laugh at Folks Who Claim to Know it All.