Our Brand's Better than Yours
A few examples from the olden days:
Turn-of-the-century advertising for Hower's Oats stated rather frankly that if you bought bulk rolled oats from your grocer, then you could probably expect to find some vermin in your oatmeal. They were promoting their packaged product over the stuff commonly sold from barrels.
Early on, General Mills used the allure of the Betty Crocker test kitchens and the concept of "kitchen-tested" recipes to win over homemakers, even offering tours of their Minneapolis kitchens. Heaven forbid you should use a recipe that hadn't been previously tested by the "experts" in a state-of-the-art kitchen.
Almost a century later, the food companies play hard ball in the game of advertising, it now being quite common for one company to directly diss their competition by name.