The more likely explanation is the slotting fees retailers charge to have the products in the store in the first place. It is easier to sell a bunch of space a

The more likely explanation is the slotting fees retailers charge to have the products in the store in the first place. It is easier to sell a bunch of space and have that space occupied by the manufacturer. Depending on the product, the manufacturer can be responsible for filling the shelves and maintaining the display. As an example this is usually the case for Frito Lay products.