Audiophile switch sellers purchase off-the-shelf switches, ditch the noisy switching mode power supply (SMPS) that came with it, repackage the switch with a small linear power supply (LPS), and sell it at a huge markup.
The LPS will in fact yield a significant noise level reduction. In other words, the product they're selling actually performs pretty well.
The only issue then is that they're selling, say, $80 worth of goods for $500, with no other expense than maintaining a website chockfull of audiophile puffery.
In a way, we can look at these people as arbitragers, leveraging audiophiles' lack of interest in or familiarity with basic network equipment.
All the more the reason to be a well-informed community - it's good for our wallets! 😃