I followed up and California government continued to be helpful, noting that we... can access numbers of GATE students in DataQuest for 1998-99 through 2008-09, the last year that CDE collected such statistics. Here is the link http://data1.cde.ca.gov/dataquest/ and the subject for the search would be “enrollment”.

This would really only be to draw a graph proving or disproving my hypothesis or interpretation that gifted is "losing" in California.

Yes, even when GATE programs were funded, were they based on native potential or on achievement. Some districts still have them, there are still a couple magnet schools (e.g. Merman) but it will be harder to collect statistics going forward, since there is no centralized source.

Personally, I'd like to at least have a GATE program. Only then can we start second-guessing it.