>copyleft itself only needs to exist in order to "undo" the effects of copyright. Public domain would be a trivial solution to the global problem if copyright didn't exist
This I must disagree with. In this world of no copyright, how do I prevent people from taking my code, making interesting changes to it, and distributing the binary without sharing what they did?
Copyleft uses copyright to make it against the rules to violate the user's "four freedoms". I don't know whether we'd be better off overall in a world without copyright or copyleft, but there would be no way to guarantee the freedom of your software's future users.
Note that it's perfectly possible to explicitly cede copyright protection by putting your work in the public domain even today. Note that copyleft is nevertheless much more popular for software than "raw" public domain.
>copyleft itself only needs to exist in order to "undo" the effects of copyright. Public domain would be a trivial solution to the global problem if copyright didn't exist
This I must disagree with. In this world of no copyright, how do I prevent people from taking my code, making interesting changes to it, and distributing the binary without sharing what they did?
Copyleft uses copyright to make it against the rules to violate the user's "four freedoms". I don't know whether we'd be better off overall in a world without copyright or copyleft, but there would be no way to guarantee the freedom of your software's future users.
Note that it's perfectly possible to explicitly cede copyright protection by putting your work in the public domain even today. Note that copyleft is nevertheless much more popular for software than "raw" public domain.