[0815test]

> Also, there might be a more interesting consideration at play in this particular case: if a work is never published, then AFAIK, it never enters copyright

This isn't really true in the U.S. AFAICT - unpublished works do enter the public domain, 120 years after creation. It is true elsewhere, e.g. in Europe, but the standard for publication is lower than you might expect; if one can argue that the work wasn't genuinely private to the author (e.g. copies were made, it was used for public performances, etc.) that's enough to consider it "published".