It's called fiduciary duty and it's why every mega company sucks.
Cut costs by replacing cashiers with self checkout? Write a fat check to the shareholders! Then, shoplifting is becoming an even bigger issue from the self checkout... Cut costs again by preventing shoplifting by having people man the self checkout! Write another fat check to the shareholders!
Nevermind that it would have been easier and cheaper to just keep the system we had. Looking at you, Target.