What you're saying may have been true in the past, but I think the days of retail and/or list price being a valid reference for wholesale cost are pretty much gone. The rise of the internet retailers has made the "retail" price irrelevant, since their margins aren't dependant on having a showroom, displays or sales staff.
I think "list" is quickly becoming a travesty. The manufacturer can call "list" whatever they want (see MSRP...)-they know damn well that there isn't a retailer out there that will actually GET that much for their product, unless it's in a full service retailer that doesn't discount...and those are few and far between....
The only exception may be in the more esoteric high-end stuff where the dealer base is small and/or demand outpaces supply...there won't be 40 different online retailers price-warring the thing, so they can get a decent margin on the product. The other exception (at least in HOME audio) is a manufacturer like Bose, who absolutely controls dealer pricing and will not allow their product to be advertised under list. Dealers that violate the rule can and do lose their distribution rights for Bose products. (The funny thing about that is that, IMHO, Bose products generally SUCK. But the average consumer thinks that Bose stuff is great because of the way it's marketed....so they're willing to pay a premium for the product...poor bastards...).
