It's all about the publishing industry trying to cram the new technology into the old business model, much like the music industry tried to do. Parts of that fit in the ebook model (writing/editing/typesetting), parts of it don't (the physical components of publishing, shipping, remainders etc). Publishers need to start looking at the process from the ground up, separate from the pbook marketing process, and see how they can best earn income with the new reality. And they'd best do it quickly before the market decides for them.
I'm not totally convinced that Baen's method is the best long term strategy either. (That's not a criticism of Baen - more than anyone they've thought outside the box and found a way to make income from ebooks, both current ones and backlist material that's been out of print for years.) Most writers have multiple publishers, but consumers don't tend to care who publishes a book, just who writes it. Some sort of retailer is a good thing for consumers, who (in general) probably aren't going to hop from publisher to publisher looking for a book.