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.
"Only 8 months" tells you nothing of the conditions or prison population within which he will be placed. 8 months in solitary or in a maximum-security prison (where hard-core, repeat-offender murderers and rapists are) is much harsher than years in a minimum-security prison.
Julian Assange, who hasn't even been convicted AFAIK, has been kept in solitary in a maximum-security prison while only being accused, falsely it turns out, of non-violent crimes. The reasonableness of the entire punishment must be taken into account, not just the duration.
Interesting modelling exercise but until we have physical evidence that this is occurring, and can calibrate the model to what degree, this is just an interesting hypothesis/story. Models are always subject to the GIGO and built-in-assumption confirmation problems and are always wrong, just sometimes useful.
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.