Actually, there's a great deal more to copyright than just protecting the author's creative contributions or additions. This article by Rabbi Israel Schneider, this article by Rabbi Yirmiyohu Kaganoff and this PDF by Rabbi Chaim Jachter all provide a nice overview of the different means by which rabbis have traditionally framed the problem. To give a brief example here:
The very first case of Jewish copyright infringement occurred in the middle of the 16th century (only one hundred years after Gutenberg introduced movable type printing to Europe!), when Rabbi Meir Katzenellenbogan (the "Maharam" of Padua) produced a new edition of the Rambam's Mishne Torah. Almost immediately, a rival publisher (a non-Jew named Marcantonio Justinian) printed another edition of the same text and made it slightly cheaper. The Maharam had not composed the Mishne Torah, nor had he composed any commentaries to go with it, and Justinian had not utilised the Maharam's type-set. Nonetheless, it was still deemed to be wrong.
Rabbi Moshe Isserles (the Rema) placed a retrospective herem upon anybody who purchased the cheaper version, argued that doing what Justinian did constituted an infringement of hasagat gevul, and mandated that all future Jewish books receive haskamot that make the nature of this ban clear. In later years, Rabbi Moshe Sofer (the Chatam Sofer) was to disagree with the notion of a retrospective ban, but acknowledged the need for this type of copyright protection: if you do not guard the interests of publishers, nobody will take upon themselves the financial risk of publishing a Jewish book, and Jewish books will all disappear.
There are other interesting cases discussed in the three articles to which I linked above, including one that involved a publication of the Shulchan Arukh together with a commentary that was not in the public domain, and one that involved a ruling of Rabbi Yehezkel Landau (the Noda BiYehuda) on a case that involved the publisher extorting the author. On each of these issues, there is more than one way to understand the basis of the halakha, and interested parties should look into them for themselves.