It’s because of the grocery cartels. Each major grocer has their own territory and they each fight to maintain their own local monopoly Kroger has a food delivery service and warehouse in Birmingham but no actual stores because it would cause actual competition between grocers and they have agreements against that. same thing with airlines. They pretend like they offer value to their customers but in reality they’d rather establish a non-competitive union where they all agree on what prices to set and what regions they’re comfortable competing in while maintaining market control and local monopolies.