The government here is structured to make public schooling answerable to local concerns and funded by local taxes. It's the barest minimum government you can apply.

Private schooling only amplifies the issues with this system. It has all the same problems, along with not needing to be transparent or accountable to the public.

I think part of this stems from how much power the states have, to be honest. There's no overarching system of, say, education that can really be used to hold States accountable for what they teach and appropriation of funds and such. Sure, they're bound by some regulations if they accept federal funding, but it's nowhere near enough. They can choose willy-nilly to just change it up, by stopping the federal funding...which is often a decision made on politics rather than what's good for the kids.

Not to mention that American secondary schools are going through an identity crisis, as I see it.