No, it's not. If it were, the school day would be more closely in line with work schedules, rather than being about 6 hours long and starting/ending at wildly

No, it's not. If it were, the school day would be more closely in line with work schedules, rather than being about 6 hours long and starting/ending at wildly different times depending on the child's age or just what school they attend. Parents generally have to supplement supervision at school with beforecare and/or aftercare programs of some sort.