It's not that simple or clear cut. Companies may reduce prices for any number of reasons. Canon has a pattern of introducing products at the highest price they believe the market will bear (what company doesn't?). Usually, you will see a high initial price and then gradually they reduce that price, generally through instant rebates. For camera bodies, the price will often stabilize after a year or so and remain relatively constant, dropping slightly during the lifespan of the camera, until near the end of that life cycle, when you often see quite significant drops.
Is the product "losing value?" Well, maybe. But it's just as likely that Canon wants to hit sales goals and adjusts prices based on hitting those goals. In addition, you have the retailer's own motivations. It's been awhile, but there a time in the not too distant past when retailers were circumventing the MAP price by offering additional discounts (often with a "show price in cart" system). Dealers also can bundle manufacturers special deals and get around MAP pricing by doing that.
Dealers get special pricing on volume and on bundles and may pass along some of the savings to consumers. In short, it's too simplistic to make a blanket assumption that discounts are proof that a products is losing value.