Meanwhile, the vacuum requires maintenance, repairing more frequently, as it runs more often. Power on time of motors is 7x as much, eg daily instead of weekly. And the robot takes more care, so each clean is 2x or 3x run time of a human. So 21x usage rates, and run time is parts wear and tear time.

Edge cases handled automatically by a human doing the task (getting stuck), means for the robot case that manual interaction is still a thing. Occasional, yet not making autonomous behavior, human free time.

Emptying the vacuum bag is a thing too, some things are not abstracted away.

Every time you add an entirely to a task, the task time goes up. Coordination is a time cost.

The savings you suggest are often not so stark. Not even for our friendly vacuums.