@gardenstategal - I don’t know if prep schools consider college admissions when admitting students. So many prep schools are PK3-12 grade. They can’t possibly worry about what college a 3 year old is going to attend can they? My kids made the switch in 6th grade and most of the kids had been there for many years already. At the senior dinner they ask all the kids to stand up and ask them to sit if they have been there for 2 year of HS, 4 years of HS, MS, etc. At the end there are always quite a few kids standing who were there from the time they were 3 or 4 years old.
At the school my kids attend faculty are required to have their kids attend and they get a great deal on tuition so there are plenty of middle class kids. The school offers need based financial aid and for high school only and competitive academic and fine arts scholarships for high school only. While there are plenty of kids in the school with modest incomes there are also some really wealthy kids there. The school is a favorite of professional athletes and international business people but the student body isn’t homogeneous.