Why Expensive power Cables when Romex behind Wall?

Systems reproduce upstream content using upstream power sources (except some battery powered phono pre-amps). In that regard we spend ridiculous amounts of money. But our systems are (hopefully) designed to do the best job possible with the presented content and power source. So we spend our money to minimize changing, or losing, the content and to doing the best it can using the power available. But I'm in the camp which says that with my upmarket equipment the equipment designers have designed their equipment based on the known vagries of the power source (one of the design decisions requires overspec-ed transformers for example). So what the hell. Let the equipment do the job it's designed to do.

Having said that I've upgraded my PCs ! Just in case. If nothing else I get a better connection to the romex. Sad really.

I may be naive and this may garner some 'flames' but ... I've got to believe that the main impact of upgrading a PC is not to do with the cable but more the CONNECTION. Hello ? There are two of them. One to wall recepticle, and one to the equipment, if I understand correctly. My guess is that if you simply unplug and replug an existing PC you'll end up with a better connection and hence, hopefully, improved sound. Cleaning these connections would help to.

Freezing them (I'm in Tahoe) - does this help ? Bummer that it only gets down to -20c here in winter and the better half would be distinctly uphappy if I opened the windows and shut down the stove to improve the sound ;-)