We will do it because we benefit ourselves from having this infrastructure. Certainly the people who first conceived of these systems were passionate about sewer maintenance, no?
The difference is we will not need to coerce people into working 8 or 12 hour shifts, so we would also have more time to devote to other interests and become more well-rounded individuals than we are under capitalism. We see things like sewer maintenance as undesirable drudgery because of how that work manifests under our current system.