A couple reasons off the top of my head, 1.) You can’t let 20-30 kids loose without it ending in pandemonium, but you need kids to practice time management skills before college. Homework is a time where kids can learn to manage a workload, outside of the controlled environment of school. 2) Kids can’t candle a 9 to 5, they need recess and art, and music, and gym to give their brains a break. In the 7.5ish hours that kids go to school, there’s probably only 4 hours of work done. (but Bob, I only work like 30 minutes of any given day, and I’m an adult…)