can't argue with your logic aside from (as someone who pushed carts for months at various Walmarts across South Dakota) the part where implementing coin-for-car

can't argue with your logic aside from (as someone who pushed carts for months at various Walmarts across South Dakota) the part where implementing coin-for-cart setups in thousands of retail locations across large geographical areas, where there previously weren't any, and customers weren't used to the situation, seems like a negligible corporate profit incentive, when you can always hire more cheap(ish)-labor cart-pushers (and/or enlist cashiers to push carts part-time as needed...) I will say though that when I travelled to Sweden a few years ago, the coin-for-cart system was truly something to behold.