It's the opposite in my market and with my store.

I never get coupons for what I actually buy, I only get coupons for things I don't buy. Those things are sometimes related, but if I wanted the other brand, I'd already be buying the other brand.

Depending on the retailer, they may have little say in what goes on sale. I work for a retailer and 98% of our promotions are based on what our distributors and producers offer us, whether it directly says manufacturer coupon or whether we handle the discount after the fact as a scan-back/credit.