But now you're getting into scope creep. What was asked for was a robot that could clean toilets, or a robot that could make a sandwich.
I think it's another discussion whether we can make robots who each do one thing well. Roomba, etc.
Besides the space constraints with multiple robots, I think it's clear there are significant advantages in having just 1 entity that can perform all the required cleaning tasks. Much like single-purpose hardware has given way (mostly) to software, except in areas with interesting requirements (GPu etc.)