Because this turned into a bit of an essay, let me frame it: I'll be discussing your statement about not worrying about harming the advanced students by requiring more from parents than schools, and following from that to consider the OP article concept of "one size fits all."
An inverted anecdote re your statement on the the parents first point: I went to a "big east coast city public highschool". While you say that you don't see the lower effort on the top demographic as a (to your credit, personal, so I may be misinterpreting it as a generalization) problem, I'd make some following statements.
Of the people in my AP/accelerated classes, about half were _definitely_ not white collar. Parents in manual labor working 2 jobs, non-english-speaking immigrant families, etc. If we did not have what little acceleration was given, they would _never_ have gotten ANY attention they needed because their parents simply did not have it in them. It can be said that "that's their job" but even decades later I can't find any fault to their focus on providing some vestige of financial stability first.
What I'm saying is that by assuming all families CAN have the parents shoulder education is an assumption rooted in much more of what I've seen of white collar than blue collar families. Pushing all families to take this on would likely hurt those without the spare time and background far more than those with. ANY opportunities we provide in that sense will continue to cyclically reinforce those with the resources to better leverage future opportunities. While I am not disagreeing to how invaluable teaching at the home is, I see publically taxed schooling as the great leveler, where the people have the chance to reallocate some of this opportunity to where it is most effective.
Now, for the "incendiary" part of this post; where is "most effective", while I'm no teacher I can also say that a one size fits all policy with only the option of "do this material more deeply" for extention would absolutely _gut_ what little educational value existed for some of the top tier students in a comparable fashion to if you pushed the remedial classes into middle school calc. If I've learned one thing from decades in school, (and as an interesting tidbit, supplemented by years of open offices) it's that humans are so hilariously far from "one size fits all" in how they learn, and while reasonably consistent in "you'll get to do less of this near-purgatory experience" being FAR more of a motivator than "you'll get to do more", it's individualization and communication that bridges this gap, not regimentation.