Honestly I think people who shell out $300 for a reader don't mind paying for books, but many of those kinds of customers HATE DRM and hate the possibility that they are 'renting' ebooks rather than buying them. Also they hate the fact they can't loan an ebook to a friend.
For those reasons you sometimes get affluent people pirating books. The publishers pretty much shoot themselves in the foot with DRM. There are already very cheap chinese no-name readers, so DRM and ebook pricing are what's hurting them.