I read that book in a philosophy class when I was in college. It's been a while, so maybe my recollection is poor, but I didn't think it was so much about dumbing-down of American education as about the methods and material that was being taught in the education system. I thought he'd felt that we lost our way in terms of our moral and general philosophical examinations of life (largely consequences of relativism) and were too driven by certain cultural pursuits like business, technologies and entertainment and such, with a lack of self awareness for what motivates how we shape our lives.
I guess this response is a bit off topic, but I recall finding the ideas in this book really interesting, and wonder if my recollection is totally off. Maybe I need to reread it... pretty sure it's collecting dust my bookshelf somewhere.