i had seen a french fry machine prototype but it’s the maintenance costs and sanitation issues such as dealing with the oil, not to mention mechanical issues.
you would need to outperform microwave foods and fast food places in taste, speed, and costs.

i’m not saying its automatic fail.
japan has a hamburger vending machine but its these terrible hamburgers in a can.
when i was in japan 20 years ago there was a cotton camdy machine. it was a cylinder shaped robot. in the body was what looked like a washing machine. a tube above it would drop pink chunks of sugar into the center then it would spin out the cotton candy. you open the door and then get the cotton candy. that was actually the hard part, since no one really knew the proper way to do so.