The funny thing is, Amazon probably could do a good delivery restaurant business. There are already many "delivery only restaurants"[1] Uber Eats encourages others to start them. But Amazon, unlike Uber, is capable of building physical infrastructure. The future of this is "food fulfillment centers", large warehouse spaces which house various specialty kitchens. Common functions, such as shipping, cleaning, equipment maintenance, and order handling are shared. Surprising that Amazon didn't go that way.
[1] https://ny.eater.com/2016/9/26/12717518/delivery-only-restau...