Why couldn't a restaurant impose a "delivery fee" or "tip fee" as part of the order?
I place many orders online these days, and most include a tip option. But I do not have them delivered, so I do not know if a delivery driver shares in any tips, or if one could be added to the delivery charge - as long as the driver and not the delivery company got to keep it.
I always tipped other delivery drivers (mostly pizza and Chinese food) in addition to any delivery charge the company added. Maybe that's why my food always came sooner than their estimated time.