Kriston, your big picture GT education thinking is very important. I guess I generally don't think about that, because in a sense I'm in the trenches, dealing with individuals; and time is of the essence. That is limiting, as a whole.
I think the problem is, that no matter how the education is accomplished when the child is pre-college, they all go into the same tube at the end, hence the problem. All kids are supposed to get good grades and good SAT scores and such. The backlash to any gifted education(these days) is the kids are seen to get an advantage to college entrance. So the gifted education is challenged, watered down, eliminated; or becomes a kind of college prep.
Times have changed. It used to be easier to get into colleges, this has certainly been detrimental to gifted education. Which is really sad to me, because obviously, the college standards for admission have ruined the lower education. With the current college situation, I can't see how gifted education can improve ideally.