Coupons I can deal with. Rebates piss me off. I check fatwallet sometimes and I don't know if the discount they show is instant or a mail in rebate until I click. So annoying.
I guarantee you there is data somewhere that says when a consumer buys more product A, they also tend to buy more product B and/or product C. So, if you give a discount on product A you can make more money selling extra B and C. That is just one possible example.
True but that purpose has never been to lower the price to the consumer. Lowering the price is a tool the retailer uses to accomplish other goals.
It is unfortunate that retailers play these games....