Then some store, to save money, had the shoppers come in and shop for themselves - so he made the grocery cart. It didn't go over well at first.
I would go back to that system. Have the groceries sitting in individual cages and coolers that can be watched by one guard and can be opened with a credit card, or have one or two attendants that can take cash.
The prices probably wouldn't change much due to fewer to no product loss. And if the shoppers complain, tell them “Well, it was either this or we were going to close down and move 50 miles away.”
You can order online at my grocery store, and it’s waiting when you get there. Not because of rampant theft, though.
I remember the old country store that was close enough to walk to from the surrounding community. They kept candy and Ice Cream and mostly canned food and all displays were on shelves behind the counters that ran both sides of the building. In front of the shelves was bagged or barreled foods such as peanuts, potatoes, etc. It was very difficult to snatch and run from those stores. If it didn’t work there was always the shot guns along the check out counter. I loved that store and the candy the groscer would hand out to us kids.