If people won't even listen to written works, why would they actually read them?
I have never liked audio books. Even the best of them that I have heard always seemed to drag on (and on.) Recently Fictionwise offered an audio version of a book that I was interested in. The ebook was less than 1/2 the price of the audio version and even by their metrics could be read in far less time than the time required to listen to the book.