When I worked in the retail photo industry the only thing we sold as MSRP was projection lamps but that was because we ended up eating the cost of many "bad" ones. Cameras, lenses, accessories, film, etc. were all sold below MSRP. Years ago I did work for one retailer who believed they should be able to sell cameras at MSRP but they went out of business because their competition didn't feel the same way.
The manufacturers did set minimum advertised prices though that we didn't go below. Those prices were established to help keep smaller shops in business. You could sell below that price but the penalty for advertising the product below that price was losing co-op dollars. This is the money that the manufacturer paid for advertising. Most retailers couldn't afford to advertise without the co-op dollars.
Irony: The opposite of Wrinkly