Certainly there are those who say the IQ tests themselves are discriminatory. I'm not qualified to say how much truth there is in that. But that is the likely reason they went away.

In my case I changed schools in the middle of second grade. A month later teachers submitted their list of students who should be admitted the the G+T program. Obviously I didn't make the cut since my teacher barely knew me. My parents tried for years to get me into the program but the district held firm that I had missed the window. Ultimately, I ended up third in my graduating class and attended a top university. The outcomes from the G+T kids were mostly disappointing. One teaches at a university, another works at Walmart. The rest are somewhere in between but mostly closer to the Walmart end of the spectrum.

Maybe I actually dodged a bullet.