Not all children are of school going age. Not all parents work strict 8am-5pm office jobs. Some schools/school districts already start late. A large chunk of the country doesn't have problems with daylight because of location.

My overall point is - the equations of labor, electricity, fuel, school, daycare, geographical times and more are complex enough in this country today that it is okay to let individual schools/offices etc. pick what timings best work for them rather than artificially trying to fit everyone in the same mold.