Plus you need to add that the more people come back with a positive feedback, because "they heard a clear improvement", the more people follow the others and also "hear something".
The snake oil products of the audio industry are on the same level like homeopathic products in healthcare. For decades the advocates of these sugar pills fail to prove that they work beyond the placebo effect, yet people still believe that you can mix an active ingredient (more like some kind of basic chemicals like coal, chalk or even chemicals causing cancer) with sugar, shake it in a specific way (by knocking it against leather), then to thin it down even more by taking a small portion of this "energetic enhanced mixture", mix it with more sugar, again knock the mixture against leather in a specific way, and voila, you have a medicine which one the one side works in a better way than the the undiluted raw chemical but without the negative effects of that chemical.
And people buy this shit. There is a whole industry selling sugar at a the same price like pure silver, and it is big business - just like the one with the cables.
Side note:
If you run across one of these homeo believing persons or even believe in this on your own... what do you do if the sugar fails and doesn't help? Do you take two pills instead of one or to you slice one pill in half and eat less? If you take two, you already have broken the most important rule how these sugar pills should work and you follow the traditional rules of chemistry and physics.
The hifi is a hobby, not a phylosophical path or a therapy. since the dawn of time human beings have invented snake oil.