OK - put down the bong and back away slooowly...
Fact: you can successfully teach Down’s Syndrome children to read and do basic arithmetic. IQ under 85 ? Yes.
Fact: in the United States over 40% of the population is functionally illiterate. Average IQ: 100
Fact: many kids “graduating” high school today are barely performing at 8th grade levels. Those who don’t graduate ? Worse, obviously.
IMO it has very little to do with intelligence and everything to do with curriculum and the quality of the teachers in 1st thru 4th grades.
If you have ever taught 5-6 year old children, all kids, even the kids with low IQs are eager, excited, and bursting to learn. By the end of 1st grade, the combination of incompetent teachers using useless curriculum puts these kids on a fast track to illiteracy.
Give every kid a competent teacher and a phonics curriculum, and you’d be back to 97% literacy in every class the first year.
That's hopelessly naive. You assume that the kids in these schools just walk through the door, ready to learn. That's a very poor assumption.
I know a teacher (a very good one, btw) who works in one of the tougher elementary schools in town. It's probably fairly mild by Detroit or Chicago standards, but even at her school the kids come from ghastly situations.
She spends a significant portion of her day just getting the kids to the point where they can think past their mother being beat up by her latest boyfriend; or the kid himself was beat up by his mother and the boyfriend; or they didn't sleep much because of the drug deal that went bad out in the hallway. Often they're considered to be a burden, and their parents just dump them for the day, and the kids know it.
A "competent teacher" in that situation will be successful if she can just create a kid who can approximate civilized behavior for a few hours a day.