Almost every kid at those 30k schools is on tuition assistance and scholarship that is why they cost so much only one out of 10 is actually paying. Additionally while they make have Christian religious sounding names they all went secular decades ago.
That makes no sense.
Many secular private schools, like the one in DC where the presidents' kids went, WON'T TAKE scholarships and don't have tuition assistance.
Even if they do, the dollar amount is capped to avoid any constitutional issues. It's the SAME AMOUNT, no matter which institution the parents pick: Public school, charter school, home tutor, secular private school, or religious private school.
Whatever the scholarship doesn't cover, the parents pay out of pocket.
In Florida, the most an elementary student from a family of four can get (income around $50,000 a year) is approximately $6500. There's no way a lower/working-class family could pay for a $30K/year private school, EVEN WITH a state scholarship.
That's done on purpose, partially to keep the school segregated by class. In other words, it's to keep black, Latino, and poor white kids out. They'll take the gamble that the handful of minority parents that can afford their fees will actually have kids with some sense.
Most private schools are religious, often attached to or on the same property as the churches that run them. And (depending on the state), the majority accept state scholarships/school vouchers.
That's why, here in central Florida, we have all these cute black and Latino kids in private school uniforms. I see them in Wal-Mart, at the bank, and in the malls all the time. And those uniforms will have the school's name, with the word, "Christian", or the particular denomination (Baptist, Catholic, Lutheran, etc.) in that title.