[jonathlee]

Intellectual property and physical property are entirely different. Intellectual property can be shared/multiplied/given away indefinitely while still being retained by the originator while physical property cannot.

After copyright expiration, the original author of intellectual property can create derivative works even after their copyright expires (in the same universe, etc.) or even updated revisions, which restart their copyright for the revision. Even if other could do so, I suspect the market for their derivative works will still have a preference for their works vs. others who create derivative works of the original, depending on the quality of the derivatives.

It is really hard to own land (or any other physical thing) after you've sold it but the same is not true of a novel.