Is Originality Still Possible?

The British literary critic Christopher Booker claims that there are only 7 original stories, and that all other stories fit into one of the following 7 categories:

1. Comedy - A story with a happy ending, usually romantic or family-oriented.
2. Tragedy - Hero with a fatal flaw meets a tragic end.
3. Overcoming the Monster - Basically man vs. nature...or the supernatural I suppose, whatever.
4. Voyage and Return - The hero faces his or her trials by leaving and then returning home.
5. Quest - The hero makes a journey for a symbolic item or person.
6. Rags to Riches - The riches in question can be literal or metaphoric.
7. Rebirth - Where the hero finds a new reason for living or is given a new lease on life somehow.

If you think about any movie, book, play, game, etc. you will see that every single one of them fits into one of the 7 categories above or is a mix of a few of them. How is it then that so many stories can be made that capture our imagination and are hailed as creative masterpieces? Obviously, it is more than the basic plot of a story that makes it original. The characterization, descriptive elements, writing style and voice all play a part in a story's originality. Look at Star Wars. Its the basic hero journey/redemption story thats been told as long as words have been recorded, but for some reason multiple generations adore it. Love it or hate it, its a good example of an already-been-done idea that still manages to seem fresh and exciting (Lucas isn't even that good a writer or idea man, but I digress).

At this point though, after so many centuries of humanity creating stories, are we in danger of losing our originality? How long will it be before every story really has been told, or will that ever happen, and why? It seems like everything nowadays can be written off as "X meets Z". Fringe, one of my favorite new shows, can easily be described as "X Files meets Heroes" (or whatever two shows it reminds you of). Its an awesome show, but I have to admit it pretty much has been done before, just not as good. We're even at the point now where simple one-off stories are being made into franchises because the first one made money, or old ass properties are being "reimagined" for a new (stupider?) audience. Its an obvious example of the business end getting more creative control than the creative end. Why bother thinking up something new if you haven't wrung the life out of your cash cow? All these things just point to a loss of creativity. There are some original things out there, but they seem to be getting fewer and farther between.

Will we get to a point where there is no new way to tell these 7 stories, or will human ingenuity and progress keep imagination flowing?