For starters, many people have rigid work schedules and do not have the luxury of getting their kid to school at an arbitrary time.

Based on this statement alone you can conclude that schools function as daycare. Why can't your nanny take your kids to school? Because you likely don't have a nanny, and don't see the need for one as school is a sufficient substitute. You could also say you can't afford one but then by demanding the school operate during work hours you're passing the cost of daycare onto the school system.