There are many quite rational anarchists who would argue for that. Personally, I wouldn't advocate for throwing that switch in today's world, because we only have like 5% of the infrastructure needed to support a healthy anarchistic society. But if in the future we have a fairly complete complement of anarchistic technology and culture I could rationally argue that copyright would be superfluous, if not outright harmful in that world.

Nothing makes these works more valuable, its just the jurisprudence has caught up to modern applications of the law. Copyrightable work is an asset much like anything else I should be able to leave to my heirs, why should I be limited to making money off my work during my lifetime or any other arbitrary period of time. Especially because there is case after case that establish work that becomes popular only after the death of the creator.

So I will ask you your own question turned around, why as the creator of a work should I ever be forced to give up my rights of the same to the public?

You are not encouraging any additional creation by making the copyright indefinite, you are simply handing creators exclusivity enforcement forever at the expense of the public.

As a creator you are not entitled to ownership of information, it is given to you by the government. It is not relinquished from you to the people. Copyright is a social contract, not an inalienable right arbitrarily given to creators simply for the act of creation.

In the first Supreme Court case on Copyright, they ruled:

“Congress… by this act, instead of sanctioning an existing right… created it.”