Russell:
I credit the success of the speaker wire industry to their expert sales and marketing ability. However, it is my experience that ordinary copper wire, as long as it's heavy enough, is just as good as name brands.
Looking at this from a different perspective, there will always be those who will want expensive wire, not because there is an audible difference, but because they may value pride of ownership and prestige in a similar way to that of owning a Tiffany lamp or a Rolex watch.