Wonder if they included academic books in that count. One of the things that made me realize I wasn't cut out for the academy was the fact that you're expected to write a book and hopefully get it published, knowing for a fact that it's not going anywhere. Indeed, if you attempt to do anything that might change that (by, say, writing with more accessible prose) you are greeted with skepticism, if not hostility.

If that side of the publishing business died, I don't think anyone would miss it.