This doesn't address the issue of whether teaching the way schools teach is actually not very effective.

Self directed learning (which is basically unschooling) is so powerful and it's not uncommon for kids to go from zero reading to reading thick books (like Harry Potter, for example), within 6 months.

Kids/people have to want to learn and it's hard to manage that in a school setting.

I know as an adult that I can't learn things that I'm not interested in, it's the same for kids. And the curriculum is generally not very interesting.