I wrote: "Real people would have to do the cooking, though. They’d also have to put the package together and hand it through the window."
Apparently, real people won't have to hand the food through a window:
Wendy's announces plans for underground autonomous robots to deliver food orders to vehicles
These have already been deployed at some Chik-Fil-As to have a second lane at the drivethrough. They’re related to those classic vacuum driven capsules used in motor bank drivethrough stations.