There are, basically, two traditional rationales for copyright:
Economic: It behooves society to motivate the creative people to create things, by allowing them to reap the rewards of their creative labors.
Moral: The fruits of ones mental labor are as much yours as are the fruits of your physical labor. If you make a thing, then it is yours.
These are both perfectly fine reasons for creating some sort of notion of ownership of creative work, some notion of intellectual property and some legal machinery around doling it out, managing commerce in it, and protecting it. Both have a hidden assumption, which is that such fruits of creative labor are in fact creative and original. This is typically made explicit in the legal machinery.
There is no economic benefit to giving ownership of unoriginal intellectual property to the creator. In fact, doing so undermines the economic benefit. If I can simply change the name from Harry Potter to Gary Motter, J.K. Rowling's incentive to write drops quite a lot.
There is no moral right to unoriginal creative works, since the was no labor. Replacing Ishmael with Bob throughout isn't creative labor, particularly, and does not result morally in ownership of a new edition of Moby Dick.
At this point the attentive reader may have detected that we have a problem with photographs and copyright. The vast majority of photographs made today are nothing like original. It is, for instance, essentially impossible to take an original photograph of the Golden Gate Bridge. A photograph of the Golden Gate Bridge made today therefore enjoys no particular right to copyright. In fact, I submit that the copyright on such a photograph could be easily broken, should someone choose to go to the mat and take it to a judge.
Obviously there are original photographs still being made, ones with a copyright that would stand a concerted legal attack. There are also many that might or might not. Finally, there are some with a copyright that could certainly be broken. It is probably a safe bet that many photographs have a secure copyright that, in the light of the opening remarks here, it probably should not. The courts, in general, do and should tend to side with the author when there is doubt.
The real situation, however, is that essentially all photographs have usage rights which can be purchased for less than the cost of breaking the copyright in court. I can buy usage rights for stock all day long for pennies an image. I can buy usage rights from people on flickr for, well, not very much. Certainly a paltry sum when compared with the costs of a legal assault.
Essentially, we are in a situation in which some unknown percentage of the photographs made have a copyright which is a sham, but nobody cares to remove the curtain and reveal that the copyright is breakable. The courts have happily arranged a situation in which is is cheaper to simply live with a lot of silliness and outright injustice than it is to sort out any kind of just and reasonable truth.
This is true, of course, far more broadly than with issues of intellectual property.