This is definitely not the case for public schools in CA, for the most part. That's why I'm basically forced to sending my children to private schools at considerable cost ($30k/yr/child).
Someone up thread seemed to think the average student of another country would blow away the average US student. I don't think this is true. The US pays lip service to universal education more then most other countries. Unfortunately we don't follow through on it and this leaves a large enough number of substandard schools to make a significant impact on US test averages. The sad fact is the tail end of these averages are so bad they bring down the score, but the "average" for the majority of US students is much higher.
This stratification of education is probably a significant contributor to the stratification of wealth in the US, and it's not OK.
I am assuming you are talking about K12 education. That is pretty absurd.
[1] https://www.cato.org/publications/policy-analysis/they-spend...
California currently spends about 10k per student for public education. That makes 30k sound crazy, but in 1970 California spent 5500 which is about 35k in 2017 dollars. California (and most of the US) is woefully underfunding it's schools.