Real answer…
GPS accurate enough to tell the car where the lanes are.
Drive thru wouldn’t be too bad, it’s essentially stop and go traffic. Plus, when full autonomy happens, drive thrus will become less common. You can just pre-order your food while the car is driving you to the restaurant. The restaurant will tell the car how long the food will take, and what parking spot to use. Then your car will tell the restaurant your ETA, and notify them exactly when you arrive. Food is waiting, so you just grab the bag and go.
Yeah, except central heating need the fan running to be effective, which is electric… So gas heat doesn’t even work without power.