Audio manufactures are like meat butchers, they want to sell the highest quality product at the most competitive price and they will let the consumer "season" it to their taste.
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?