The walmart closest to me only had self checkout and got rid of ALL of their cashier lanes. They had 4 times ad many self checkouts. That lasted for a few months. It went from taking 5-10 minutes in checkout to 45 minutes or more. Why? Untrained people are slow and the software is terrible. In addition, Shoplifting went through the roof.

They finally added cashier lanes back in. No idea if it was complaints or dropping revenue that caused the reversal.