I'm not surprised. Amazon's entire MO is a relentless focus on the customer. They do that by methodically optimizing and controlling every aspect of the supply chain right up to the moment the product is handed off to the customer. And they get better at it every day.

Restaurant delivery breaks that model. There is too much variability. Too much can go wrong outside their control, and they don't have enough leverage to change it.

If they can't win (even at zero margin) and can't make customers consistently happy, why be in it at all?