Perhaps it is as simple as Dealers want large margins so that they can discount because we, the customer, want a discount. We always feel better when we get a discount... :)
Why do designers/manufacturers...?
If audiophile grade feet, power cords, and fuses can really improve SQ, why don't high end designers/manufacturers just incorporate these audiophile grade components at the time of build? Why sell an under-optimized item that can be easily improved upon by the owner or a modder?