How about just upgradable versions? Say an author puts out a novel, and then over the next year, does some further edits, better character development, whatever. Why not put out a version 2 of the novel?

Same question with music. Especially now, with so much music worked on in software rather than recorded to tape, it would be easy to spin out a version 2 of a single or an album.

We do see this in some other areas; textbooks, for example, routinely have multiple editions with various updates.

It seems really odd to me that we don't make updates to all sorts of media.

But then, lots of folks were perturbed at the updates to the original Star Wars movies...