Ok, so right here is the issue. It's like saying that US has no poverty issue, because some of the richest people live here. You yourself mentioned, that it is important to improve the bottom percentiles. And the bottom percentiles in California are not good. Some of the exceptional schools in CA are private, some of them are public, but most likely located in expensive areas. You gonna have to pay for a good school either directly or via insane home prices. Yes, you can find decent schools in less-crowded-but-not-very-rural areas with more reasonable cost of living, sort of a sweet spot. And the majority of those schools aren't gonna be exceptional, the will be fine, just fine. Not better than any other state. But the lowest percentile in the worst area is still gonna drag the whole chart down. Everyone I know in CA who cares about school for their kids either lives in a pricy area or pays for a private school.
As for Lowell, I think that was a big issue for many, but not amongst the 100+ parents that I’ve spoken to on the issue.
https://wallethub.com/edu/e/states-with-the-best-schools/533...
Ranked 42nd overall, 36th in quality and 51st, ie last in safety.
The US weirdly in general has a lot of high ranking universities, but its elementary and secondary schools are very very uneven, at any level.
OTOH, just a few miles from some of the best public schools in the country you can also find some of the worst. While California is segregated, most Californians nonetheless live in relative close proximity to people living in vastly different circumstances, so disparities are very evident.
Let that sink in.
https://www.usnews.com/education/best-high-schools/georgia/d...
https://www.usnews.com/education/best-high-schools/californi...