One data point, but I heard from Brad Feld that when writing Do More Faster he found the publisher to be really good at taking a Word doc and converting it into a book (and all the editing that goes into that). He found them to be pretty much useless when it came to actually marketing a book. That probably explains why he's self-publishing his upcoming series.

It seems to me publishers will have to figure out either how to get better at marketing or evolve into low-cost specialty printers.