John, your post also pretty well describes the cutthroat discount store world here in the US as well. Not fun and it always feels kind of slimy.
When I got my Beosound and Beolabs, since I bought them from a large chain store, I managed to get some discounts. I bought the Beosound when they had a storewide "buy any receiver and get X% off" thing, so I saved a little on it. Got a better deal on the Labs, as they had a buy any speaker and get the 2nd at half price. I'm also sure that B&O didn't like seeing their items discounted, as with premium gear, it's hard to say it's worth X when people discount it, there is a perception of quality that is hard to maintain in that market.
Back when I was in college was right at the end of the Fair Trade Act era, when manufacturers could absolutely control how much things cost, no discounts. So, in order to work deals most stores would have it so you buy a system, table, receiver, and speakers, for a discount, and they'd use a pair of "black box" speakers (that is speakers that are total crap and made by some junk speaker vendor, usually with a store name on them). If questioned they'd say the discount was on the speakers, not the other gear. Speakers would be something like 500 bucks retail but really cost like 40 dollars to buy.
Then that era ended, and at the time the mass market gear like Pioneer and other imports would have a price sheet that said:
Cost 10% 20% 30%......100% markup, you'd get a guy on the hook, pull your book and say, well, let's see what I can do here. Then you'd look serious like you were thinking, move your finger from the 100% "retail" cost, slide it down to like 60 or 50%, and say well I can sell it to you for this, if you buy today. I hated it.
Cartridges always had huge markups, I bought a $125 Audio Technica for $25 bucks. That was about typical. These days since there are no cartridges sold, mostly, the huge profit items are wires.
The good brands always had a max markup back then of 30-40%, which is about the minimum you really need as a dealer to pay for your overhead and keep the lights on and the sales help paid.