I agree with that 100%, as well as with your and EinNYC's comments about failure starting in the earliest grades. It's hard to teach a fifth grader any subject when the fifth grader can't read or do math at even a second-grade level. Except in very unusual cases, abandon hope when that fifth grader has become an eighth or tenth grader who can't read, spell, or do simple math.
One of my friends in the homeschooling group here - Tom’s debate coach, until Tom discovered cuter girls in science competition - moved his family into the area of the best high school in Charlotte-Mecklenburg, because he planned to send his children to public high school.
However, by the time his oldest child reached 9th grade, the district had eliminated most of the academically advanced high school programs and cut back on staff for what remained, because their priority is to try to teach the lowest-performing students *something*.
Maybe they could have, with a massive push on phonics and math-facts drill in the first and second grade, but there’s nothing to be done by the time they’re 14. Well-off and motivated parents can homeschool or send their children to private school or pay for tutors. The biggest loss is to the brightest and hardest-working students from lower-income families, who no longer have challenging courses available to them, and have to spend their high school years with “students” who don’t want to be there and are disrupting the environment for those who do want to learn.