Let Teenagers Sleep
The real blame for early high school is extra-curricular sports. Basketball, Football, etc.For those sports to thrive, teams need to practice, in order for practice to be efficient, it needs to be at least an hour. So 2 hours are allocated (suit up, practice, suit down). In order for children to be able to commit to 2 hours extra of their time BEFORE their parents get home (5pm), class would have to end by 3pm. Now, pair that with the fact that most school districts don't have enough bus drivers for every school, they pair up. A single bus driver will start their day bussing high school, then will bus elementary school (which starts later in the day). So high school ends a little earlier so the bus drivers can bus the elementary school kids home after they bus the high school kids. In order for the kids in high school to end at 2:15pm for sports and to save money on bus driver employment and bus fleet, they have to start 2:15pm - 8hr: 6:15am. It's crazy. It was like that when I went to high school in the early 90s, it's still the same today.