Wasn't the original discussion about robots replacing human labor? A single human can do those things.

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.)