The shops know this. High-end hifi is full of grift. It literally relies on people with more money than sense who can be persuaded to spend a fortune on components and extras that either make no difference to the sound or make it objectively less accurate.
Which is why you get nonsense like directional cables, cable supports to keep cables off the floor, cables with magic insulation, magic rocks that go on top of components, magic knobs, magic creams, "quantum" anything, grounding boxes full of pebbles that don't ground anything, and so on.
Also, most of the people who can afford this hobby are rich old boomers who often can't hear much above 7k on a good day.
Which is why you get nonsense like directional cables, cable supports to keep cables off the floor, cables with magic insulation, magic rocks that go on top of components, magic knobs, magic creams, "quantum" anything, grounding boxes full of pebbles that don't ground anything, and so on.
Also, most of the people who can afford this hobby are rich old boomers who often can't hear much above 7k on a good day.