The question is missing the point the parent is making. Parent is saying that the purpose of IP is to, in the long run, benefit society. As a result, we have co

The question is missing the point the parent is making. Parent is saying that the purpose of IP is to, in the long run, benefit society. As a result, we have collectively agreed ( for various definitions of agreed -- I certainly think they are way too long ) that protecting author's works for a period of time is desirable. As such, after some time has passed, why does it not end up in the same category as old published books ( public domain )?