Lol, the commercials for said cereal were always literally about everyone saying it was cookies for breakfast, and who doesn't have the same breakfast every day? If there was a box of cereal, that's what we were eating until it was gone and then you open the next box of cereal or switch to toast/waffles/pancakes/biscuits/oatmeal until that box is used up, and so on and so forth until it's time to go back to the grocery store.

If your parents bought the cookie cereal (and there were apparently enough to keep it on the shelves for years) then you were eating it everyday as a normal thing.