I can understand private school when it fills a clear need that public does not. The public closest to us is 80% English language learners/subsidized or free lunch, so most parents who are more affluent and educated choose something else for their kids. Whether there really is a need there or not, I have no personal experience. I could be convinced that if the majority of the school population has one set of needs and your kid has a different set of needs, the kid may be netter served elsewhere. Who knows?
The second biggest need in my area that sends kids to private school is language immersion. We have a pretty diverse set of neighbors who send their kids to school in Spanish, German, French, and Mandarin. We are lucky to have found a public Mandarin program but no French or German in public yet. With one kid it probably doesn’t make a big difference but once you have two or three kids, it seems to me you would be better off selling and moving someplace that offers what you need in the public system, even if you have to pay a good bit more for housing there.
My kids attend schools like these. For elementary, we transferred from a school of 95% free lunch and 70% ELL to a school with 75% free lunch and 50% ELL.
Our junior high is 85-90% free lunch.
(Both schools provide free lunch to all students, as do many schools in our district. Including some of the wealthier schools.)
Our teachers at the elementary level are quite good. I would say that historically, the school we attend *used* to be maybe flipped. Only 25% free lunch and 25% ELL. So, many of the veteran teachers are very much able to challenge the higher performing children. Both my kids have done/ are doing fantastically well. Where we have historically failed is actually with the ELL students. ELL students at our school don't do as well as ELL students at richer schools. Not surprising - they have more (PTA) money to spend on teacher's aides.
This will vary quite a lot on the individual school, teachers, and even the grade level. Both my boys have "grade levels" with a large % of high achieving students who STAYED (vs transferred to the GATE program at a different school). The grades before and after my older son were not so lucky. Fewer babies that year, far more opportunity to transfer. So there may have been only 1-2 (grade above) or 3-5 (grade below) students who are high achievers. So fewer people to work with, study with, and egg on, so to speak. I cannot really blame parents for giving it a try for 2-4 years and then transferring. The key was to give the school a try.
My 2nd grader had a classmate in 1st who had attended the school we are zoned for. She was concerned that in Kindergarten, he was one of the top students. In 1st at our school, he was far behind. That is a possible risk if you are in a school with 95% ELL - you may stand out as being awesome, but be behind students in other schools.
I think many of my friends think similarly of my kids - my jr high kid attends the "worst" (public opinion only) jr high school (the poorest one and with most % of Latinx). But ya know, he still got a perfect score on the state tests, so he's good. Would it be better or worse for him to be 100% surrounded by kids like him or better? Who knows, really. I don't feel the need to have him surrounded by only the best, smartest, rich white kids. Some kids REALLY have different needs. My kid is a GATE kid, but he's got pretty normal educational needs. Some other kids have higher needs, different needs.