Why should a company that provides no differentiated value have much of net margin (after paying for the cost of capital, in the form of debt payments which are

Why should a company that provides no differentiated value have much of net margin (after paying for the cost of capital, in the form of debt payments which are included in company expenses)? Kroger et. al provide no unique value - they don't have any intellectual property, they have almost zero human capital because they treat their workers terribly and have low retention. They do some stuff with their private labels but that's really it. What grocery stores doing that commands more than a 1 or 2% margin on a huge segment of the economy? If they're earning more than that it is probably and indication that they are ripping off the consumer, ripping off the worker, or both.