Forgive me but as someone who has a fridge, microwave, stove and oven, delivery does not appeal to me.

There is a whole frozen pizza in the store that sells for 3 dollars, and a slice of pizza from the 7-11 that goes for 2 dollars. Pizza delivery is the one food where delivery has matured, and even today it's a very limited buy.

When do people do it?

Parties -> Almost any demographic

Workload is too high to go out -> Students and younger adults

Going outside is extremely uncomfortable and/or dangerous -> Primarily older

Unmotivated and lazy -> A small fraction of any demographic

The thing that can finally drop prices as we know it is the quadricopter. A self navigating delivery channel has at least reasonable chance to bring the price well into tolerable levels for most americans.