The robot can also sit around doing nothing without complaint and for no extra cost. So the robot need not be used 100% of the time. Even in SF the robot will not be used much at 2am.

Though I was referring to the small cities in Montana. Nobody will put a robotic burger joint where there are no people. However a town of 5000 has a lot of people who need to eat, more than enough to make it worth running numbers.