Who owns the commons?

In chapter four of his book Convergence Culture, Henry Jenkins writes about fans using the Star Wars universe for their own videos or literature, and LucasFlims prohibiting parts of this appropriation. This battle between the producers and the consumers raises the question, who has the rights to these media productions such as the Star Wars movies? Is it the producers who create them, or is it the consumers who have grown up with them, explored them, and may better understand them?
Furthermore, is the determination of these "rights" a legal question, an economic question, or it philosophical matter? Jenkins mostly discusses the legal and economic aspects, but it can be more interesting to examine the philosophical issues involved. Beyond the need for a profit, is it moral for companies to prohibit fans from creating new movies or literature from the media that the corporations "own"?
Jenkins mentions the anthropologist Grant McCracken as writing: "Ancient heroes did not belong to everyone, they did not serve everyone, they were not for everyone to do with what they would. These commons were never very common." He argues that classical stories were never for the mass public to enjoy, but only allowed to be told by certain people in certain contexts. Thus it may be normal that popular contemporary stories may not be for public use either.
However, our stories, such as Harry Potter or Star Wars, I think have become a part of our shared culture. And there is something disquieting in the notion that we don't own our culture, or even have rights to innovate on it. Instead, massive corporations do.
This ownership might be a side effect of capitalism. Maybe we're supposed to participate in our culture without changing it. But even if the Greeks had similar notions of the "commons," this idea still doesn't sit well with me.
Similarly troubling is the concept that these media conglomerates themselves have adapted parts of this culture from other sources, but are now prohibiting anyone from adapting it for their own purposes. Jenkins writes, "The older American folk culture was built upon the borrowings from various mothers countries; the modern mass media builds upon borrowings from folk culture; the new convergence culture will be built on borrowings from various media conglomerates." I think he means that each new step in the progression of media will involve content borrowed from the previous step. However, some media companies could prohibit this borrowing by the "convergence culture" from occurring in the future. Jenkins quotes Lawrence Lessig as noting that the laws have been rewritten so that "no one can do to the Disney Corporation what Walt Disney did the Brothers Grimm." Thus the media giants could be trying to prohibit others from appropriating what they themselves have taken.
This appropriating and the banning of "users" from truly using the product has all been done for a profit. And the need for more profit may also end some prohibitions on use of privately owned culture. Jenkins writes that the studio and publishers will have to make some concessions, which will be "hard for the studios to swallow but necessary if they are going to exert sufficient moral authority to reign in the kinds of piracy that threaten their economic livelihood." In other words, the new media convergence will cause the corporations to adapt or fail, because they need consumers, and these potential consumers can now go elsewhere with new technologies if the companies alienate them. Nevertheless, maybe it's just a product of the capitalist society we live in, but there is something further disconcerting to me about the idea that these philosophical issues could be decided because of the need for a profit.