I guess that's the difference between the city schools and rural schools.
Growing up the busses would pick-up all kids along the route regardless of age (we only had 1 Elementary, 1 middle, and 1 high school). I was on the furthest bus stop from the school and it would take 45 minutes to an hour to get the 5 miles home. Some friends on other routes would take 1.5 hours to get home via bus because the district was so large.
The bus that picks up my son for 1st grade only services the elementary, and he's not on the bus for more than 20 minutes dispite living only 2 miles away. In our area, there are 3 elementary schools feeding each middle school and 3 middle schools per high school.