There are THOUSANDS of public schools in the US. Some are excellent, some are essentially baby sitting services.
They are best in prosperous neighborhoods where nmost of the parents are also well educated, They are worst in poor neighborhoods in which the parents are poorly educated.
Poverty is less of a contributing factor with many Asians, including Koreans, Japanese and Han Chinese, because of the reverence and respect that parents in these communities have for education, which is different from other groups, including the descendents of rural African Americans, American Indians, some Hispanics and some rural immigrants from Southeast Asia, such as Hmong and Cambodians.
Homeschooling follows a similar pattern: the wealthier and better educated the parents are, the better the education tends to be.