Teachers can definitely have a large impact. But students spend 80% of their time outside the school. You could have the best teacher on the planet, but if they're not getting reinforcement from outside the system, there's not a lot you can do. If three wheels have their brakes stuck, it doesn't really matter how fast the fourth is turning, you're not going anywhere. It's not that we shouldn't work on our schools, but we have to approach raising children holistically - it's not enough to have them in school for 6 hours a day for half the year, we need parents to be involved and we need to make sure those kids are getting a basic level of stability outside of school.

Then there's the Hierarchy of Needs issue. Before you can really learn and grow and develop, you have to fulfill your basic needs. If you're starving, then the only fractions you're able to focus on are fractions of a sandwich.