Unfortunately, it’s my understanding that this sort of thing winds up politically impossible in most parts of the US, as segregated-by-ability classrooms wind up looking uncomfortably like segregated-by-race classrooms.
The schools weren't fully separated, the GT classes was one designated class (1st-5th was English, 6th-8th Science).
The AP classes were highschool and college credits and you could choose English, Math, and/or Science.
This was in Texas. Though they no longer do GT classes anymore I don't think. Those were my favorite as a kid though.
Asian schools are great at providing high test scores. Their rigid education really drills the information into the kids and works well.
But that incredible strictness simply would not work with most American children. The culture is simply incompatible with the strict discipline involved (and that’s not to say it’s bad, but only different).
America’s trouble is that there are some majorly divided cultures living together, all under the label of “American”. What works for some people just won’t work for others.
Poorly performing students are often the ones who are “physically disciplined”. My most successful friends are generally the ones who had very supportive families who’d struggle to even raise their voices against someone.