With Roomba quality software a blower, an electric pressure washer, a few soap reservoirs, valves and maybe a squeegee can do the majority (by time) of a janitor's job in a bathroom more thoroughly. Being able to press "go" and have it find the floor drain, wash-down everything in the room below a set height and then herd all the water to the floor drain with the squeegee and blower and make a noise when it's done or needs to be refilled.
You're not replacing the janitor just narrowing the scope of their job. Putting up the toilet seats and letting a robot foam and pressure wash them down with some chemical you can't sell in California (so you know it must be good) is a big improvement over cleaning toilets manually, especially for anyone with back problems.
Or corners, or windows, or sinks, or counters, or stoves, or bathtubs. Nor do they take out the trash, or even dump their own waste into the trash. Nor can they do the laundry or the dishes or dust, or fold towels, or go up and down stairs...
