I agree. And I think the amount of schooling should depend on what they want to do.
In the 19th century kids spent fewer hours and days in school and learned more in 8 years than kids learn now in 13 years. With computer classes, kids could easily outpace the current crop of high school graduates in 4-5 years.
In other words, by age 10 they would have a superior education to what 18 year olds get now. Then they would be free to pursue higher education or specific job training until they were 16 or so and could pursue employment.
I realize I'm dreaming big.
Believe it or not there are public school systems where kids can specialize in job related skills starting in the seventh grade. In this same system my daughter earned two years of college credit while in high school, and she was just typical in her program.
I think you're on track.
Most important is reading. Teach someone to read and, given the desire, they can learn anything else on their own.
The more complicated subjects require more assistance. Mathematics comes to mind, as does science, and, imo, writing.
Most of the other subjects are based on reading and/or absorbing: humanities, social sciences.