Brian,
If the point of your example was to compare brand new Monster brand interconnects or speaker cable to 20 year old corroded poor quality wire, then you are correct, the Monster cable will sound better. But, Monster will NOT sound audibly different than any reasonably priced interconnect with even moderate quality connectors. Some good mic cable and some terminals from PE would save you a boat load of money and I would guarantee you would not hear a difference.
Monster does have some legitimate technologies they implement, but to imply that they make wires for different styles of music, tells me the are marketing snake oil. If it isn't snake oil and it sounds different, they are adding acoustical filters to change the original signal, a la MIT. Sorry, but I will pass on them EQing my cables, i prefer accuracy.
BTW, no one is saying to buy crappy wire, what we are warning against is buying into the marketing [censored] on the market. Next thing you know, you are going to mention "skin effect"...Just buy some wire with some nice well-built, secure terminals and you won't hear a difference. Wait, let me take that back, it will not sound different, but your mind may trick you into thinking you hear a difference.
Oh, and yes, I have been pressured by sales people as have 99.999999% of the people who have worked with salespeople. Afterall, that is their job, if they weren't trying to sell me something they wouldn't be doing their job. Luckily, I have the luxury of not being ignorant about consumer electronics and regularly correct and if necessary, humiliate sub-moronic sales people who don't have an ounce of technical knowledge.
