SF School district has 55,000 kids in public schools. It is the 6th largest school district in the state of California. They sit behind Los Angeles, San Diego, Fresno etc. In addition to 55k kids in public schools, they have another 22,000 kids in private schools. SF has a low number of kids per household, but it's still an enormous school district.
The prompt was speculating that there aren't enough parents in the SF school district to enact change, my response is not addressing California schools in relation to other states.