It really all depends on where you live. I moved to a good public school district when my son was in middle school. His public HS was named one of the top 5 schools in the US when he was there and many pro ball players and CEOs of huge companies had their kids there when they certainly had the money to send their kids to private schools. He received an INCREDIBLE education and mostly took AP classes. In fact, since it was a public school, they paid for college classes if they couldn't offer you what you'd take next. For instance, he had a girlfriend who took senior AP classes her junior year so they paid for her to take college classes her senior year in those subjects.
When I was growing up I went to private schools from 5th grade until I moved in with my Dad my senior year of HS - all that money gone to waste when I graduated from a public school, lol. But again, it was in a great area and everyone I graduated with went to college and most of them are a lot more successful than I'll ever be with my mostly private school education
You do what YOU think is best for your kids - that's what parents do!