A lot of popular media and art are owned not by their creators, but by clients or other corporate entities.
Despite my fantasy-self's obsession with owning intellectual property, I am one of those people who wants to be in control of his own destiny. I generally take the Harry Potter goblin view towards creation - the true owner of something should be its creator, not necessarily its client. But of course that depends on how personal the nature of it is anyway. Chermayeff & Geismar & Haviv never meant to hold onto their iteration of the NBC peacock, for instance.
Comments
generally, though, I think the creator should own it unless they give/sell it to someone else.
(philosophical answer)
Everyone who thinks about it.
Everyone whose lives are influenced by that creation.
Everyone who has ideas for making sense of that creation.
Everyone woh has ideas for building on that creation.
A creation becomes public domain (in the social sense, even if not the legal sense) when it becomes public. It becomes everyone's -- everyone who comes into contact with it and becomes aware of it.
(legal answer)
Original creator or creative team.
10 years: exclusive control of copyright.
after that, an additional 20 (or even 10?) years: guaranteed royalties from for-profit derivatives. Derivative works that are sufficiently transformative are allowed. Not-for-profit derivatives need give no money, but any profit from derivatives pay royalties to original creator; derivative works are allowed even if the creator does not consent to them. Derivative works' copyright works the same way for those works' creators, except for the part of the content that comes from the original creation.
after that: public domain
Derivative works of original creation, also by original creator, have their own copyright. In this case -- if a creator keeps the creation "active" -- copyright can be renewed by original creator, but not for more than a total of 20 years before derivatives become automatically allowed and royalties automatically due.
Creator of original creation can choose to waive any part of this control at any time. Not sure what if they want to regain it within the original timeframe, or regain it with a renewal.
That's how it SHOULD be.
^ edit: i have been ninja'd