Things that are and are not surprising

It is not too surprising that academic publishers do not wish to take on dissertations that have already appeared on the 'net--although in fiction, at least, some authors have successfully released work online that was then picked up, also successfully, by a mainstream press.  (Then again, there's a difference between buying a book for $11 and buying one for $110.)  But it is surprising that a press would think of a dissertation as equivalent to a book, when, at best, most dissertations are a rough draft in need of extensive polishing before they can become a book.  My own double-decker dissertation went through some intensive chopping, revising, combining, and adding before it underwent its final baking into Book One; I certainly wouldn't send anyone to read the original, which is very, well, dissertation-y.