I tend to see a bit of a belief among some educators and parents that there is "equal ability" and that all children are capable of being gifted if given challenging work. I have attended a number of school meetings where parents have voiced the opinion that all students should have access to the GT classes/teachers/curriculum b/c they would all benefit from it.
One of the schools my kids attended for a while seems to be trying that premise out by putting almost half of the kids in TAG programming for at least one subject.