I mentioned before that I had loved the book Why We Sleep, by Matthew Walker. It has changed my habits. Now the University of Washington finds that a later school start is improving outcomes for highschoolers. Of course it does.
The difficulty is that parents want the extracurriculars, especially sports, as much as the students do. I was tied for the most activities in highschool according to the yearbook, in a class of 424. And that wasn't the half of it, as I had other activities unrelated to the school. Church. Y. Music. Theater. Football. I now think those things were not very valuable. There is some value in working together toward a common goal. There is some value for the whole student body, and even the community at large, to have something to cheer for. Just not a whole lot of value. Not compared to being awake in class, and marginal kids having less time to get in trouble.
School should be school. I didn't think so twenty years ago, but I think so now.