It is a fair point thought. Bad employees can drive down profits, scare away certain customers, and hurt the bottom line. Sadly there are some very toxic places out there where such an employee would be kept because they fit in with the culture and management style of that particular store.
There is one store a couple of towns over most of the locals knew to avoided. The owner on down are very hating of the customer and you wonder why they are even in business in the first place. While they certainly could be getting a lot more business they do get some of the off flow from more tourist heavy traps and thus they don’t care much about the customer. There will always be another that ended up not knowing better.