This doesn't work in real life for a few reasons:
1. Childcare. Older siblings often watch younger siblings after school until the parents come home from work. That's why older kids start first. So they are home when the elementary schools let out. From what teachers told us in High School, it's often the law that it's done that way during early closings (weather events). By shifting the schedule, you now make families shift that child care burden and cost.
2. Reduces the consecutive block of hours that a teenager can work. This is important for those who need to contribute to pay the bills, or cover their education (college) in the future. Yea they get more morning time, but it's hard to work 2 hours, go to school, then back to work 2 hours. What business wants to accommodate that work schedule?
Overall, it's fine for the wealthy, but it really punishes poor students and their families.