Some is good, then more is better?

There are some cable companies (ie. Morrow, Clear Day...) and others. I list those only for reference and not to be singled out as there are lots others. Anyway their entry level speaker cables use "X" amount of wire, then as you move up the product line they use 2X, 4X ... Well my question is other than the slight decrease in resistance, what are you getting to justify the jump in price? I realize more wire costs more money, but how does the sound improve? Some of these companies put in customer testimonials that state significant improvements. It's the same thing, only more of it. Does reducing the overall gauge of the wire really improve the sound that much?

I know I have put in more than one question, but I would like to see a discussion of this topic. Thanks