Well no, it’s about legally gating the ability to copy so the original author doesn’t have to compete in the same market to sell his own book with every other bloke with a printing press and a copy of the book. Everything else is an addendum.
That may be the reason copyright came to be, but it's much more expansive now.
No, it's to promote the progress of science and the useful arts.
The current implementation has recently become obsolete.