Always thought Walmart combined sophisticated algorithms at the distribution center end with idiots at the store end. I remember being addicted to Diet Doctor Thunder (it's a drink, it's a laxative) about fifteen years ago. My local store ran out for months on end. Eventually the slot for it on the shelves was removed. I asked at other stores and was told it was the largest selling house-brand drink. Turns out the whole process relied on a single kid that decided constant restocking could be avoided and his job made easier if he just ignored stocking the shelf. No stock, no sales, Bentonville shuts down the deliveries. Called the grocery manager who seemed surprised and it was a big seller again.