Are you suggesting that digital goods cannot be sold and can only be licensed? What is your basis for this? It seems to me that this was a sale of goods. The fact that the goods are in digital format is irrelevant. It is unlikely that the courts will treat the sale of a book the same as a software license. Ultimately sales of goods are governed by law, and one party is not permitted to breach their contracts.
This depends on the exact meaning of sale. It is certainly possible to implement a license agreement, that looks very much like a sale of a physical object. However I think that such a license agreement would be unenforceable, essentially because a physical good has a certain uniqueness. It makes sense to talk about 'my car' which is distinct from 'your car.' ( And if someone steals 'my car', I am able to identify this specific car.) By contrast, I can not really talk about 'my mp3 file' because there is simply no difference between my file and any of its copies. This applies also to watermarked files, since given a copy of a watermarked file you can not determine if this specific representation of the file was created by the original licensee or from an intermediate copy.
So the important point of me buying a book, is that a unique physical object becomes mine, by contrast there is no such thing as a unique digital object. [ IANAL, it is entirely possible, that there is some case law which defines a sale of software. But my point is, that this would be kind of a default license.]
