they simply need to run a good ordering/inventory system. If they sell every item (on average) in each store every week, that's 2.39% return on the value of the inventory investment each week, or 52*.0239 or over 100% annual return on money they borrow for free because the store pays its grocery bills to suppliers in arrears, net 10 days, etc
What I mean is: If you're making 5 cents of profit per item, and your workers cost $10/hour then the difference between a profit and a loss is 18 employee seconds per item.
they simply need to run a good ordering/inventory system. If they sell every item (on average) in each store every week, that's 2.39% return on the value of the inventory investment each week, or 52*.0239 or over 100% annual return on money they borrow for free because the store pays its grocery bills to suppliers in arrears, net 10 days, etc