A lot of this is a Google search away. Here's an article from vox that is well researched: https://www.vox.com/22841191/gifted-and-talented-education-p...
It's puzzling why you won't lend credence to an important factor: poverty has cognitive consequences. Yet rather than trying to improve the lot of those students, you're fixated on taking things away. This is how socialists think: some people have it too good and need to be punished.