Most teachers already have their classrooms open at lunch, not that lunch is long enough for most extracurriculars. And where does the money come from for expanded subsidized child care? For those who do take a duty-free lunch, they need that time to recharge. You can't do sports during lunch, and that is what would keep students the latest. 

You're right that school is about student learning. But part of that learning is also preparing them for life, to be a productive member of society. To be able to function in a workplace, and the reality is that your typical supervisor sent going to care if you're tired or don't want to get up as early. You could argue that it's a temporary need during adolescence, but there are young people who work right out of graduating high school, over the summer, on weekends, etc.

It's an opportunity to teach perseverance and resiliency, and that sometimes things aren't going to be given to you or that sacrifice is required to get ahead.