HBO canceled Carnivàle, a serial show with deep mythology, after two of a planned six seasons. The remainder of Creator Daniel Knauf's story was never told.

The AV Club :: Daniel Knauf tells us his plan for the end of Carnivàle

AVC: Have you ever considered trying to do it as a novel or a comic book [of the remaining story line]?

DK: Constantly. Yeah. Marvel, we had it all set up. At one point, they wanted to go forward and do a series of graphic novels, and they just couldn’t turn the corner with HBO. Since then, yeah, I’ve considered it. But one of the things that makes me a little crazy about Hollywood is, they’re idiots when it comes to their contractual stuff. If I write a novel, it’s like Random House publishes the novel, copyrights it, but when you do business in Hollywood, they say, “Everything in this thing, in all forms, in all potential forms invented and uninvented…” The language is draconian! “…throughout the universe. We own everything in your head. We own everything.” And it’s like, “If you own everything, at least exploit those rights, please. Could you please exploit the rights? And if you’re not going to exploit the rights, can I at least have them back, so I can exploit them?” It’s just a silly way of doing business. [...]

It didn’t make sense to spend $3.5 million an episode. So let’s do a graphic novel. Let’s tell the story!” But they’re on to other toys now. It’s like doing business with that kid down the street whose parents give him really bitchin’ toys, and he’d just leave them broken in the backyard. It makes me crazy, Hollywood.

I think you could make an analogy to Georgist taxation here, or perhaps more generally Gobry's argument in favor of the French wealth tax.

If property ultimately derives from mixing your labor with things, it's not unreasonable to suggest that people have an ongoing responsibility to continue doing so. If you hold some property, most especially land, you may have a responsibility to society to put it to productive use. (We're talking about theory here, not practice. The arbitration of what counts as responsible, productive use is nearly impossible in practice and so even if you had such a responsibility in theory it is likely best if that responsibility is never legislated into reality.) Gobry's argument is, briefly, that capital gains taxes discourage people to put their resources to use, while wealth taxes do the opposite. In essence, capital gains taxes makes it more expensive to put your resources to work, so people do less of that. OTOH if you're going to loose %1 of your accumulated resources anyway to a wealth tax that gives you reason to put your resources out in the world to try to get them to grow more than the amount you'll lose.

If a studio owns the rights to further adaptations in other media, do they have a responsibility to society to actually use those rights? Land may be a special case of property, because people aren't making any more of it. Or so I gather the Georgists, the Diggers, etc. would say. But people aren't making any more Carnivàle either. That idea can only be invented once, only to be owned by one person, just like a particular acre of land. Does that put an extra responsibility on HBO to do something with it? If an owner of arable land has a onus to see it cultivated, does the owner of fecund IP have a similar onus to see it reified?

I have absolutely no idea how you would actually structure this as a policy. Doing so in a way that wouldn't put the actual tax burden on the creators rather than studios would be harder yet. Even so, I think it's an interesting way to look at the ethical responsibility of content owners, if not a way to structure their legal responsibility.