Monstrous power cables

"The electricity is carried through my house probably using 14 gauge wire."

This is the key.  Same with streaming.  If your bandwidth from the curb to the house is bad, a 1000$ router is not going to make it any better.   If the source is bad, it will not get better with a different cable to the streamer.  You don't want the power cable to make the sound be any worse, but hard to understand how it going to fix the 50 feet of Romex in the wall, and Romex don't cost much per foot.  

Honest question. Can someone explain how a expensive power cord is going to over come the 50 to 100 feet of Romex (about 1 $ per foot) that runs from the breaker box to the outlet? I can understand if the stock power cable was worse then the Romex, thus creating a bottle neck, but it seems to be the very long run of inexpensive Romex that will be the ’weak link’, were the electrons to care. And, I am all for listening, but it must be a blind test. 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.