I get that you want the best possible sound... and in some cases the placebo effect may actually help you enjoy your music more... but are there really enough of these people to base a business on?
If you're effectively making a cable that costs maybe $10 to manufacture, but selling it for $340, you don't need many "audiophiles" to make a significant profit. If you have a few hundred of them, you're already making 6-figure profits. (Obviously some cables may cost a little more to manufacture, but certainly not anywhere near as much as they are charging.)
It's kinda like wine. There have been studies that show that if you serve cheap wine in expensive bottles, people like it better. There have been studies that show that many wine prizes are awarded so haphazardly that you might as well choose them at random. There have been studies that show that actual wine judges at a major competition could barely rate the same wine with consistency above random chance on consecutive days.
And yet, people still will pay hundreds of dollars for some bottles. Recent studies have even shown that people literally get a better "pleasure" response in their brain when they are told a wine is expensive, compared to when it is supposedly cheap. It's more than a casual "placebo effect" -- it's something that people will pay hundreds of dollars to experience, even if most of that effect comes from the act of paying the hundreds of dollars rather than the product itself.**
I'm sure most audiophiles have a similar experience -- they literally receive more pleasure when they listen through an expensive cable. They want to pay more for that experience. So why not let them, I suppose? It's not like faith healers or psychics, who might do real damage with their charlatanism... the only damage these cable dealers could do, I suppose, would be with some obsessed audiophile who goes and throws his money away on expensive cables while his family starves. Maybe there's a couple people like that in the world, but it's certainly not a common problem.
And these sorts of "tests" won't convince anyone. I'm not sure what the point is anymore. It's like James Randi going after Uri Gellar -- true "believers" don't give a crap what the tests of "skeptics" say... they'll just keep believing. Let 'em enjoy their magic cables.
[**NOTE: To be clear, I am NOT saying all wine is the same. There are a lot of different varieties and flavors. But I do believe you should just buy what you like. There are $5 wines that have easily beat out $100 wines at blind tastings. So, if you like a wine and discover it's only $5, keep buying and enjoying it. If you like the $100 wine, and you like the taste enough to pay $100, fine.]