The one I loved was a pancake machine at a hotel breakfast buffet. You pressed the pancake button and batter was dispensed onto a slowly rolling large heated cylinder. When your pancake made it to the edge of the cylinder, it peeled off and flipped onto another counter-rotating cylinder. Then it was peeled off and slid down a chute onto a plate. Perfectly round, perfectly cooked.
I ate a few more pancakes than I should have just to see it work. Then against the protests of my wife I lifted the hinged side panel to see how the batter was loaded and dispensed (it was squeezed out of a bag by a screw jack)
The girl at the buffet asked if I was a process engineer (yup) and assured me that I was far from the first to peek under the hood 😅
In other words, race to the bottom is race to the bottom.
Those jobs were not cruel and demeaning as you seem to imply. In fact plenty of industries still operate that way (auto parts etc.) and they served a valuable purpose, to give work experience to that underpaid teenager.
In fact if you go to a butcher shop, fishmonger, farm market etc. you will have your food handed to you by a human as well. And most people highly rate both the service and quality at such shops, with the employees usually being paid significantly more than at supermarkets, and having proper work hours and job security.
So yes, I suppose Piggly Wiggly made food margins a little thinner. But considering I get better meat prices at my butcher than at a supermarket, who do you think benefited from that move the most? Most likely the same ones benefiting from the move towards a fully automated store like Amazon tested.