The elderly are the problem. Many of them are hoarding all of the dog food for themselves to have cheap and easy meals in retirement. At this point there is none left for the pupperinos.
I used to work in the pet industry (never again, traumatizing) and I will tell you honestly Pet Shops know people love their pets so they overcharge you. It's fucked up but it's the same shit private health and insurance does so it's not new for Capitalism.