You know the quote. Nothing's new under the sun. That saying goes back a long, long way, which makes it all the more true now. When the movie Avatar came out, it was hyped as one of the most groundbreaking movies of all time. Well, they certainly weren't talking about its originality, that's for sure.
Most things coming from commercial entertainment sources - Hollywood, book producers, video games, television shows - are simply repackaged, canned cookie-cutter retreads of something that's been done before, and often better. I Am Legend screwed over the original ending and completely schwacked the entire point of the movie, all to make it more commercial. Since then, they've packaged the original ending as a special "alternate ending". The box office is completely filled with remakes and sequels nowadays, to the point where the International Union for Conservation of Nature is considering adding originality to their list of endangered species. And how many clone cop/court/investigator television shows are there now?
It's the same with books. YA has exploded to huge popularity. Just the other day in the book store, I saw Ender's Game repackaged and reprinted as YA. It's always appealed to a younger audience as much as an adult one, but was never marketed as such. I guess they have to grab their share of the market while they can. Hell, if you're not writing about zombies, sparkly vampires, teen school angst, or even better, a combination of those, your chances for publication drop considerably.
But everyone is still looking for that outside-the-box original idea. The next new thing to hit. Something that's different from all the rest of the commercial slush out there. If you've got that idea, you've got a good chance at success. And seeing it turn into commercial slush just like all the rest of it out there. Once something is out there, the model for its success is copied and honed to perfection until it's originality is perfect - just like everything else.
They won't plagiarize, but as Avatar mutely attests to, they come as close to it as humanly possible to mimic the pattern of success they know works as a business model. Publishing is the same way, and it isn't going to change until an outside impetus jolts it from the cycle. Your main character is too young? Turn the story YA or rewrite to make him older. Didn't finish with that happy ending? Unless it's blatantly horror, you've got to change it. Even if it's horror, a rewrite might be suggested. Subject matter outside the boundaries of normal commercial fiction? Sorry, we're going to have to pass on this one. Best of luck elsewhere.
So what is that impetus? What can bring about the change from this blatant commercialized process of rubber stamping all the cookie-cutter clones for the masses? The indie market, whose authors aren't bound by someone else's decision of what's going to work? Society, whose ever expanding sense of normalcy simply screams loud enough for something well off the beaten path? The pros themselves, in an attempt to outdo each other for that latest avant garde success, or to stay viable amid the fears of an ever-growing independent push?
Hard to say. Maybe it won't happen at all. Maybe things will continue to get churned out for the masses and dumbed down to the point where entertainment is purely mindless escapism. It's almost there now, after all. I'd like to think originality has a chance. I hope it does.