Two things progressive schools don’t offer.
That many families aren’t leaving the Bay Area they are just pulling their kids out of school.
Why if not the progressive curricula?
""" Slow population growth: In the 1960s, the population in California grew 26%. Between 2000 and 2010, growth slowed to 15%, then 6.5% between 2010 and 2020. In 2020, there was a net migration loss of 0.5%, signaling that the state’s projection for the next decade, a slim 5.2 percent, may be high.
Aging population: In 1970, the median age in California was 28; in 2020 it was 38. In 2030, it will creep up to 40.
Birth rates: In the 1950s, the birth rate in California was 25 per 1,000 people; in 2020, it was 12. The previous low of 12.6 was in 1933, during the Great Depression.
Delayed marriage: In 2020, for the first time, women’s average age of marrying was over 30. """
And sorry, "slow population growth" is the same as "increasing population growth", so it doesn't explain a decrease.
The great weight of stories published on this question indicates that people are vacating to live less expensively/more lavishly, not to be with people less politically progressive. Are there a few such people? Sure. But they’re hardly the majority.
There are a lot of reasons why people choose not to send their kids to public school. Sometimes it’s because they perceive the public school as unsafe. The primary reason isn’t because parents disagree with the math curriculum, but because they want to give their kids a leg up in the fiercely competitive race to get into a top university. When everyone around you is wealthy and smart, parents try to find whatever advantage they can.