Earlier quoted context omitted.
Not OP, but I think it makes very little difference whatever number you pick between “none” and “forever”. Earlier this year a few authors whose work I enjoy tweeted furiously about this topic. Similar arguments may apply to audio and visual copyright. If, for example, copyright lasted 14 years, then The Atrocity Archives (Stross) would already be public domain, which reduces incentive to create more in the series (n…
> Making copyright last 100(average of all x) fails to harm society by preventing the work from becoming public domain That does not follow. Even if literally everyone who was interested in the work already has a copy, copyright prevents others from building on top of it. That is the harm.
Yes, sure, it would be a copyright violation to write today a novel set on a giant space artefact containing a flattened full-scale map of Earth, where a motley crew (including a bald human on anti-aging drugs) crash-lands and investigates, finding the machinery of the world breaking down, where those things are “the Ringworld”, Luis Wu, superconducting wire destroyed by a synthetic microbe, and Boosterspice; but that didn’t stop Pratchett writing Strata with “the flat world”, Kin Arad, general entropy, and Days.