The cost of educating a student K-12 is less than $4,000 per year. Businessmen who depend on schools of whatever kind to educate their future employees might wisely develop a relationship with good private schools and their students, meet the students, experience classes, attend graduation exercises, choir concerts, etc. The school building is a former junior high school purchased at bargain price from the public school district which wanted to get rid of it. Not a palace but adequate to the purpose.
May I amend that statement to "The cost of educating an average student K-12 is less than $4,000 per year."
One of the reasons that the cost-per-student gets inflated is due to the special populations that schools are required to pay for. For instance, I'm writing an educational plan for a student whose doctor wants her placed in an institution for continuing depression. He is fighting tooth and nail to get the schools to pay for it, rather than the family's insurance. The cost will be about $300K... a year...for one student. I wrote another plan last year for a set of triplets who are all in an institution, and have been for years, due to severe MR issues - the county spends about 250k on each of them. And will until the year in which they turn 22.
Put a few of those into any system and the average cost increases to levels that leave people scratching their heads with "Wait...how can possibly cost $10k per student in a classroom?"
In the case of your wife's school, and any school really, it doesn't cost more than about 5k per student - but some students cost way, way more than 5k