Maybe one problem is with the idea of GT programs. My understanding is that many of these programs are brief pullouts one day a week rather than meaningful approaches to meeting the needs of gifted kids. Everyone here knows that gifted kids generally need to move faster and/or go deeper.
Schools could fix the "move faster" part of this problem at very low cost by just scheduling the same classes at the same time in lower grades (this solution would also address the needs of kids who do okay in reading but need to repeat last year's math). A private school around here found a way to get kids from the middle school to the high school for advanced classes. It is simple. They put them on a shuttle bus. Other private schools (and our local charter school) manage to teach geometry and other HS subjects in 8th grade. Most or nearly all public schools outside of very rural areas could do this if they wanted to. But I think that many simply do not.
Oh well.
