I'm not sure that having a child growing up in an isolated environment, interacting with mostly one person, is good or healthy. I have a hunch that exposure to many people, situations and environments is better for the child, as long as the overall exposure is positive. Not only that, but the isolation of the caregiver probably makes the caregiver less fit (depression, imagination-killing-routine) to provide quality education. In that lense, I think there's solid arguments for why "farming out" might be better for everyone, child and parents.