As someone who still occasionally mixes for a living, designs and builds audio hardware: Audiophiles are full of shit and this has been scientifically shown probably since the 90s (various AES studies conducted on the perception of CD quality).

Of course there is a difference between cheap gear and decent gear. But the difference between decent gear and audiophile gear is non-perceptible in a blind ABX test. And here is the thing: especially in the elctronics side (so amps) decent gear has become increasingly cheaper.

Audiophiles also tend to have downright naive claims about sound, like the silver cable sounding more clear and "silvery" while something with gold would then sound warmer and richer. All while they measure the same down to inperceptable differences. And of course the device with the walnut case sounds warm because wood is warm and so on.

It would be funny if it wasn't auch a successful con.