In that case, why is there a societal obligation to protect the work? Copyright is a trade between the author and society. The author releases the work to soc

In that case, why is there a societal obligation to protect the work? Copyright is a trade between the author and society. The author releases the work to society at large, and in exchange, society provides a means to be rewarded for releasing it. You can own a story entirely, so long as you do not release it. Then, nobody can take it from you, and you will never see those characters do anything beyond what you say they do. But if you want to share it with others, you must accept that they will eventually write things based on it.