I could never be a mum in America. I'm too selfish. I like doing things with my kids each w/e but it's got to be things that I like too - like going to the beach, climbing mountains etc. I could never be selfless enough to spend hours watching them do endless sports just so they could get credits for college. I can't imagine my life being like that - it's actually winding me up just thinking about it!!
I know so many successful adults who have not been to top private schools, and may not have had a particularly academic schooling - bright, well balanced people will generally do well whatever schooling they have, and childhood should be a happy time, without all the pressures and stress of adulthood, I believe.
This is not to say I think private school is a bad idea, but I think your children will do well wherever they go, because you care about them and want the best for them.