I'm not sure why you find it surprising. School exists in part to provide lower socioeconomic demographics with a part-time stable environment for their childre

I'm not sure why you find it surprising. School exists in part to provide lower socioeconomic demographics with a part-time stable environment for their children. Also, workers are paid during that time, whereas children, particularly of younger age, can't really be expected to maintain concentration for 7+ hours in a physically isolated environment with no other children, or a teacher watching.