The point that, as adults we don't retain what we don't use, is a valid one. However the fact that the average American scores abysmally on simple questions of history, civics and geography, doesn't mean these subjects are irrelevant. It means the schools have done a piss-poor job of conveying the importance of learning them. Anyone can recall just enough to pass a test. Showing that the subject knowledge has value above and beyond securing a passing grade should be the goal of teaching.

I would venture that the reason why India and other Asian countries do a much better job of educating their children is because parents still stress the importance of education and require a level of achievement from their kids. Whereas here some parents who still do so seem to be more concerned with competing with their peers to get their kids into the best schools than whatever lasting benefit will be gained.

You're right, American schools do suck. The question is, how do we make them better? Vouchers work for some but they are not a silver bullet. The entire system needs to improve.