The writing was on the wall as recently as 2 a.m. this morning, and an open letter from Macmillan CEO John Sargent has confirmed everything we suspected: Macmillan books were pulled from Amazon store as part of a strong-arm tactic in the coming eBook price war. [Publishers Marketplace via Boing Boing]
It looks like DRM is a double edged sword. Amazon can charge whatever it wants for books. It buys the books from the publisher. It owns them. It prices them. It sells them.
Selling eBooks is a different. The publisher retains ownership. Amazon might try to set the prices, but it doesn't own the books. When the reader "buys" them, they do so at the pleasure of Amazon and the publisher. What a great deal.
Physical books have resale value. You can lend them to friends or give them away. You can't do this with eBooks. That's value subtracted. That's DRM. If nothing else, they should be less expensive for those restrictions alone.
P.S. You'll notice that Steve Jobs killed music DRM by allowing the publishers to collect a premium for the value added, DRM subtracted.