The "temporary" part seems to have disappeared, at least in the USA. Very, very little material enters the public domain every year. The rules about copyright (instant when fixed in tangible form, long lasting, can last for years after an author's death) make it almost impossible to tell based on the material itself, whether that material is copyright. I have to conclude that today's US copyright is an imposition by authorities, albeit a subtle one.
I, along with most commentators it seems, consider the shift to give rights to authors (over a private, closed, cabal of printers) in the Statute of Anne to be the shift to copyright of a form recognisable today.
The Licensing Act you refer to was a censorship law, not a copyright law; it IIRC doesn't protect authors rights nor give them primacy as the creators of [copyright] works.
But you should look up the history of copyright. The Licensing of the Press Act of 1662 (https://en.wikipedia.org/wiki/Licensing_of_the_Press_Act_166...) was essentially a censorship law. Copyright is censorship of a sort.