School districts in affluent areas are hotbeds of left-wing activism, but in general, student performance is at least acceptable. Parents ensure that their own children do well enough, and often invest heavily in supplementing public education with specialized tutoring that at least guarantees that their kids do well on standardized tests.
Kids get a much worse education than they should, and often more than parents assume, but there is a reason many parents are unaware of the parlous state of the public education system as a whole. If you can get your kid into a good school in a prosperous area, it really isn’t that bad, except for the ideological indoctrination.
I don’t want to oversell even the better public schools. Kids are now entering college without ever having read a book, and often with math skills that require remedial education, even at elite colleges. But parents love the fact that their kids are getting good grades and doing well on standardized tests, and will earn a credential that will likely serve them well.
Most affluent parents seem indifferent to the left-wing ideological training their kids are being subjected to, although I detect that a backlash is building and will become strong enough to force the lefties to become more subtle in affluent areas. Or not.