A quick few searches tell me that less than one percent (0.7%) of the population have janitorial jobs, at least in the US (easiest data to grab quickly here). It seems not at all insurmountable to find one in a hundred people who don't mind bad smells and just want a simple job where they can listen to stuff and not think too hard. I've worked those jobs myself, and even without good pay it is pretty nice to just listen to books or music and not have to think too hard at work. If I could thrive on a job like that, I actually wouldn't mind. It just seems like a bad example of why anarchism wouldn't work, at least to me.