That’s the reason against starting late. Parents want older siblings to be available to babysit after school and employers want a 16 year old’s shift to start at 14:30, not 16:30. Extracurricular activities (which should be supported, as long as the children themselves want to do them and as long as they’re not actively harmful to children) can often run 90-150 minutes with changing time and warmups, which makes a later start time logistically difficult for families with children of various ages who want to eat dinner together.
It’s a complicated issue and a solution which involves shorter school hours seems to me to be the best one, but that’s obviously even harder to implement without cutting things that are important, so I don’t know how to actually solve this problem.
I live in Germany now, which has tracking. This seems both hella classist and better for ensuring kids can get sufficient sleep. I would love to know if any country/school system has figured out how to do it in a way that doesn’t deprive some kids of future opportunities.