This is also the norm at grocery stores in central Asia -- you're expected to bag your food as it's scanned, and often you're expected to either bring your own

This is also the norm at grocery stores in central Asia -- you're expected to bag your food as it's scanned, and often you're expected to either bring your own bag, ask for (and pay for) some plastic bag, or be lucky and they have some form of bag at the end. Besides cultural differences, it also comes down to the fact that many people use baskets and the carts are essentially two carrying baskets fixed to a metal frame, in striking contrast to the US jumbo sized shopping cart, so you necessarily can't bring that much and can likely bag it yourself in a short timeframe.