I know this concerns parcel delivery, and not food delivery, but for anyone interested, this was a great read on why the unit economy of (non-people) delivery is super rough:
>https://medium.com/@review/the-food-delivery-death-star-85f9...
>https://medium.com/@review/the-food-delivery-death-star-85f9...
Parcels, on the other hand, well, I can tell you it needs to be here at time X, and you can do as many deliveries as possible between now and time X. (I guess that's the same thing, except that for food, X is now +10 minutes.)
UberEats is actually very expensive compared to GrubHub etc, so if anyone is making money its probably them.
Is this important? I'm not sure. I mean, it's certainly possible for kitchens to do things (heat lamps, not combining ingredients) to store cooked food longer, things that aren't done in cars, so it is possible that time spent waiting at the kitchen matters less than travel time.