Well, to paraphrase a passage from Douglas Adams' Hitchikers Guide series, high ticket items are bought "by rich idiots, to impress other rich idiots". But that's just the late author's anti-oneupmanship cynicism for you.
Somebody, somewhere, has decided that they *can* perceive a difference with expensive cable, so the trading standards authorities have no grounds to swoop down and ban their sale. Like any marketplace, there are products to suit any wealth level.
Ultimately, if *you* cannot detect the improved sound quality, then why waste your money?