I know a woman, a bit of a legend around these parts, who's been actively advocating for GT education for decades -- to the point of bringing a lawsuit against the district for not following state law in terms of gifted education (the district lost, but is still out of compliance -- over a decade later).
She started advocating when her children were grade school students within the scope of their school... her grandchildren are completing their schooling and she's still advocating, now at the state level. There has been positive change due to her advocacy, but not nearly enough compared to the massive effort she has put into it (in my opinion).
It first came to me back when we were trying to get DD (then 7) a grade skip. The principal was in favor (or so she said) but the district pushed back sharply against it. They did offer that she would be designated as TAG though.
"Do you have a pull-out program?" I asked the principal.
"No, but you could volunteer to run one!" She sounded like she was granting me a big favor and I suddenly realized that, from the school's point of view, DH and I were going to be solely responsible for our DDs education. That if we didn't get her what she needed ourselves, it wasn't going to happen.
In a way, I'm glad we had this rude awakening early, because it allowed us to be more aggressive in getting her what she needed and not waiting for change to happen. Otherwise she might be languishing in public 5th grade, bored and underachieving at school and stressed and acting out at home, while we endlessly attempted to work with the school trying to get any kind of accommodation.
I do still advocate on the state level, providing written testimony on the importance of GT education, making calls to education committee members, and passing along relevant research when education funding bills are discussed. But I'm not doing it for DD, I'm doing it for all the other kids.
