The school schedule does not stand alone.

If you start school later then households where all parents are employed and the children are not old enough to handle getting ready and out the door in the morning on their own might need to have their work schedule pushed back.

If work schedules in general then get pushed back to accommodate the school schedule change, pretty much everything else follows because work is such a big and inflexible block of time on most people's schedules nearly everything else has to schedule around it.