Thought this would make decent fuel for discussion.
I've seen schools go both ways. When I was in elementary school, gifted education was out of fashion as "elitist". My friends and I largely grew up as underachievers who were first challenged in graduate school, and had to scramble to learn study skills at that time after spending years coasting to A's. My son is in a system with separate gifted classes, but most of these classes are within general schools rather than totally segregated. He's having a much better learning experience, and is more comfortable socially (no bullying for "nerdiness"). The overall school seems to benefit, as the tracks are together for extracurriculars and recess, and the G&T parents are disproportionately involved in the PA. Average test scores also rise, which helps the school get government funding and grants for extras like music. Prior to the gifted program era, a lot of those families would have fled to private schools or the suburbs.