Terry K. - I don't think literature can be 'dumbed down', it stands on its own merit. Books, however, have been dumbed down for a very long time. Remember comics? Romance novels? Mysteries?

Music was dumbed down by video. Theater was dumbed down by movies and movies were dumbed down by t.v.

I guess a good rule of thumb might be whether or not a book stands the test of time.

As far as literary merit, Harry Potter is rated highly when compared to everything else out there. Children are a big market. At least someone cared enough to produce something of value and something that could compete with Pokemon, Dora and Transformers. Now that is crap with no literary value!