That fails to account for drastically reduced space and operating costs of self-checkout machines. In my experience one cash register is generally replaced by 3

That fails to account for drastically reduced space and operating costs of self-checkout machines. In my experience one cash register is generally replaced by 3-5 self checkout machines. Even if the cashier is twice as good at scanning and bagging the self-checkout will have much shorter lines and as a result will be much faster.