...was the Empire Copyright Act 1911, or more specifically, that act as incorporated into Australian law by the Copyright Act 1912, which in turn amended the International Copyright Act of 1886 (a spinoff of preparations for the Berne Convention for the Protection of Literary and Artistic Works). The Berne Convention began the “demise+n years” idea; the previous arrangement was the 1710 Statutes of Anne, with a fixed copyright term of 18 years. Before that, a hodge-podge of laws and arbitrary grants protected mostly the printers, rather than the authors, and were often designed to also serve as a government-controlled censorship tool.
I’m looking at the practices of Eric Flint, David Weber, John Ringo and several of the other authors who deal through Baen Books, they seem to be releasing the complete text electronically under a licence which is essentially the Creative Commons Attribution-NonCommercial-NoDerivs (ie, “you may copy this as-is but not sell it” within a few years of publication.
When they started giving away their works, sales skyrocketed. I can imagine a few types of work (such as encyclopaediae) for which this might not work so well, but even there releasing a decade-old version as nagware (“get an up-to-date definition at www.buymorestuff.com”) might work too.
Either way, this demise+70-years stuff looks sillier and sillier the harder I look at it, with one notable exception: it drums up “short-term” (ie, at the cost of longer-term volume) business for the lawyers of large publishers. And of course, who would said publishers consult about such things, and get to represent thim in Court and Parliament? Hands up anyone who thinks this hasn’t coloured the design of those laws?