Edit: I bought a Kindle anyway. They look awesome and there is a $60 off deal going on.
a) A digital version is already distributed for free at the author's page (not that it makes any difference).
b) A digital version is not even purchasable, but you can find it by illegal means (seriously? I can download the torrent but not purchase the ebook??? This doesn't even make sense!).
c) A digital version is only available at Amazon.
>update: The more we support this program the more publishers will buy into it. They have just received new dollars from me that are generally 20% bonuses above the cover prices of books sold years ago. There is no cannibalisation as I'm not in the market to buy any of those books again. I really want to get to the stage where all my books are digitised and I can choose whether for not to maintain a physical library. If Amazon and publishers provide a simple and legal way to do this then sobeit.
Netflix wasn't what it is on it's first day.
I would hope that some day Amazon would require everyone that wants to sell a physical copy join in on the program but I can see how that might damage their profits. Maybe once a majority of books are on the program they can make it a requirement and everyone selling books will have to decide to suck it up and join or not make money through Amazon.
What I really don't understand is why anyone selling books wouldn't want to join the program. Is there any scenario at all where they would lose by being a part of it?