I can think of arguments why derivatives should get more favorable and less favorable treatment than overall copying. To me it feels like a wash and they should probably be treated similarly-- though trademark can provide some limited protection beyond copyright terms if the work's use in commerce has been continuous.

The original thing has already been created, and proceeds benefit whoever created it (or who they sold rights to).

Whether they choose to continue to actively market it or not, while under copyright, can't be influenced by copyright. Abandonware under copyright is still abandonware.

But! There's a class of derivative works, built on top of the original, that currently can't get made.

If they were, we'd all be better off.

Arguably, I can even see an aggressive sunsetting for derivative works being net positive for the original work's commercial value ("See the original").

Would the copyright holders of Zork get royalties in this scenario, like with cover versions of songs?

The other problem is that in this scenario people will just be slapping the names of things that were popular x+10 years ago on literally anything. People will just make the lowest effort loot box laden pay-to-win mobile games you can get onto the App Store, and advertise them as sequel or tie-in to that old popular game/book/movie.

Debatable. Some sort of FRAND-level payment, for a limited period, seems fair? Not enough to torpedo the economics of anyone using a property. But enough so an originator has a revenue stream for wildly-popular IP.

> slapping popular names

Would this be that bad? If there were Harry Potter crap... how would that be different? Expect there'd be more stuff out there.

It's essentially a case of brand dilution. Today 'Harry Potter' is a brand that has certain values. If a new Harry Potter book shows up on the shelves tomorrow I can be very sure it's a kid friendly, easy to read, book about wizards. People can feel safe buying as a present for their niece or grand child that likes Harry Potter. In this alternate future a 'Harry Potter' book could be literally anything. If that is 'good' or 'bad' is left as an exercise to the reader, but something would definitely be lost.