The problem with many staples is (or maybe by this time, was), that they were being packaged for wholesale, mostly. Once it became that the products needed to go to the grocery stores instead, they had to re-configure the lines in the factories and re-order retail packaging to account for the new orders and then re-package the product and ship it. It's not that there isn't enough, it's just that it had to be re-packaged.
My husband works in the food industry and it's been a real challenge.
Watson