I agree, I think the culture around kids activity is not optimal in the US, and I think the primary culprit is weird urban planning. Schools are often located far away from population centers, and there is no walking and biking infrastructure for kids to get them selves there safely, so they have a massive amount of school buses to make up for that, and the whole schedule and culture is organized around limitation with school buses and drivers.
In Europe it is normal that school and kids culture is detached. There are cultural activities (including sports) which kids get them self to after school. In USA all these activities are organized by the school it self and if it is outside of the school area, a school bus is organized to take kids there. This could be so much easier if they would just build the schools close enough to population centers with enough biking and walking infrastructure that kids could get there by them selves.
In Iceland they start between 8:00 and 9:00 (and being on permanent DST this is actually worse in Iceland). So like my parent said, sports (and other kids culture) are not the reason for sleep depriving teenagers, they are merely an additional contributor.
I just felt the need to state the difference in culture here, where US kids activities are really tightly coupled with school activities. While in Europe a simple change in policy—often just on a school administration level—is needed, while in the USA, this is way more complicated.
In Europe it is normal that school and kids culture is detached. There are cultural activities (including sports) which kids get them self to after school. In USA all these activities are organized by the school it self and if it is outside of the school area, a school bus is organized to take kids there. This could be so much easier if they would just build the schools close enough to population centers with enough biking and walking infrastructure that kids could get there by them selves.