Not technically scams, obvious ones aside (ie, hundred bucks for a wooden knob or "directional" cables); audiophile gear is indeed top quality, but the excellence they aim to would never be recognizable by any human ear on the planet because the incredibly small improvements, if any, would be measurable only by lab instruments.

One can spend ten times less and still not hear any difference, but as any psychologist could confirm, once someone spends a fortune in something he believes it will sound better, he will surely hear that difference. Too bad nobody else will, unless they also fall in that trap.