That $29,865/yr likely goes mostly to pay exorbitant retirement benefits.. and it's only getting worse. In many locales, Teacher Unions have become a SCAM on the American tax payer...
This gets back to the point that you realize there are two components to the costs of most private schools - the tuition that is paid each year AND the money that is raised privately to support the school. When BOTH portions are taken into account then the cost of education is similar to public schools. Private schools connected with churches (Catholic, etc.) generally get all of their facility funding (electric, buildings, heating, etc.) from church funds. Non-religious private school generally have large fund raising divisions to get the money from alumni for non-salary expenses.
In North Carolina, we spend about $8000 per year in public education for K-12 students. I will note however that our state is ranked 49th in education and 46th in teacher salaries. The botom line is that you get what you pay for...
and from Deadwood, who notes that..."There are many private schools in the Chicago area that charge less than the local schools spend per student. The local schools are beyond horrible. The private schools range from very good to spectacular. Anytime you have a union bureaucracy to feed you're going to pay more for less." Whenever we are confronted with these apparent discrepancies, to make sense of them we have to be cognizant of not only the quality of the school from a facility and faculty standpoint, but also the quality of the students. It may be that the students in the private school being compared to a public school come mostly from stable, educated families whereas those in the public school are more heavily weighted toward students from poorly educated, economically disadvantaged families or similarly disadvantaged single parent homes. Educators have long known that the quality of the student plays an important role in educational outcome. The effect of private schools operating in competition with public schools may be to draw many of the better students away from the public schools resulting in a negative impact on public school outcomes. A more valid comparison might be to compare two very similar public schools serving similar neighborhoods, one with the faculty unionized and the other non-union. Or alternatively similar unionized and non-unionized public schools with similar students might be compared. But are there any unionized private schools?
No, and for good reason. Parents won't pay for an assistant band director or PE teacher's retirement starting at age 54.
It could be that the rise in the number of private schools is a backdoor way of re-introducing "tracking" into secondary education. Tracking in public schools essentially ended with the advent of Lyndon Johnson's "Great Society". Some people believe that this was harmful to educational outcomes. I am one of those who believe this. I don't think it is smart to force square pegs into round holes. I believe tracking was best for everyone in the long run, not just college bound students, because it recognizes that we are not all alike in our innate physical and intellectual capacities. In my opinion the message to children by the time they reach junior high age should not be the false message, "You can achieve anything," but rather the truthful positive message, "You can likely do many things well, but it will take hard work and dedication. Overtime you will discover and naturally gravitate toward those things that you can succeed at, and your success will be your own reward. We will do our best to help you reach the goals you set for yourself." This encourages self-reliance and puts responsibility for one's education where it belongs, viz., on the student, not on the teacher or the school. It was the move away from this principle that occurred with the well-intended changes resulting from Johnson's education initiative that, to a greater extent then any other factor in my opinion, resulted in the slow deterioration of public school outcomes . I am reinforced in this view by my own educational experience, and my personal observation that in the top achieving private secondary schools blaming one's underachievement on the school or the teacher is simply not an option. You can try it, but it is not going to get you anywhere but out the door.