Why do we need to secure a "right to benefit from what they create"? If it's not beneficial for authors, they can go do other things. Is there reason to believ

Why do we need to secure a "right to benefit from what they create"? If it's not beneficial for authors, they can go do other things. Is there reason to believe this will lead to a loss of authorship? Abolishing copyrights would make derivative works' authorship possible, and that's probably a more significant source of creativity than brand new works. And we're currently sacrificing it for the former one, as well as various rights.