I seriously don't understand why schools don't simply swap elementary and high school schedules. When I grew up, and what seems to still be the common pattern, is that the buses go out first for high schoolers to start school early, then do a second route to pick up the elementary schoolers who start school later. Can't we just swap those? Elementary school kids wake up earlier naturally, and this helps the parents w…
For the younger kids, each hour earlier they start is an hour earlier they finish, which means parents need to either finish work earlier (not possible for most people), or pay for an additional hour of after-school child care (expensive). Having free child care to cover the gap between school finishing and work finishing is extremely rare, and the acceptable age to leave your child unattended after school is going up due to over protective parenting (for example, I was a latchkey kid starting in the 3rd grade, but nowadays that seems almost unheard of until middle school).
For the older kids, starting later means sports / extracurriculars finish later, potentially after dark or after the parents are done working and expect kids to be coming home.