Some people do buy them, then tell others how much better their system sounds as a result. They're fucking deluded and deserve ripping off by the snake oil fucks who prey on their deluded fuckwitism.
No matter how many facts you throw at them, it's impossible to convince them that they have shit for brains, yet not one of them will ever commit to a double blind test, because deep down they know they're deluded shit-for-brains fucks, and the only reason they buy this shit is to show others how much money they have. And because they only mix with like-minded people, you end up with a cabal of shit for brains wankers competing against each other to see who has the largest pile of shit where their brains should be.