You know my grandfather told me something once, rest his soul, that there was never really just one universe. You expect something to happen and it didn't happen, but in another universe that outcome has already happened. No he wasn't a scientist or an astrologist, but he it was something he always thought of, and thinking about we got what was possibly the worst ending ever to Naruto maybe in some other universe the Naruto series got the proper ending, NS, Shinachiku, Orchimaru, SK, etc. Everything that we were all expecting to happen by the end.
I want to believe that, but still I wanted this series to go out with a bang in our universe it's something we deserved for so many years.
Your grandfather was very smart! He's basically talking about quantum mechanics! Potentialities vs. actualities and 'many worlds' theories have been wrestled with from the time of Aristotle and on. Like with Shroedinger's cat, where the cat in the box is both alive and dead until the box is opened and one state is known for certain. With the many worlds theory, the universe splits off into separate outcomes from each possibility. So instead of a continuous timeline for our univers that looks like a single long thread, the universe looks more like branches on a tree.
It makes my head hurt to think about all the possibilities. I think that's why we live in an actuality, in this one reality where our choices don't exist after we've made them, rather than simultaneously weighing all the potentials all the time. Our brains can't take it!!
There is an anime, "Noein" (which means "to my other self"), which totally wraps this stuff into their storyline, along with time travel, young romance and changing your fate. It's really, really, really good - one of my favorite anime series of all time.
As for Naruto, I think it's easy to separate the series into different universes: one where the ending impoded the whole series, and one where the ending followed along with everything that had come before.
And I think Chatte's theory was so right on — if Kishimoto had played his cards right and tried a little harder to be mysterious, he could have kept all the fandoms still connected to the series. He could have ended it with the question mark hovering over the story that Obito might have actually succeeded in putting the whole Narutoverse under his jutsu. And what we're seeing as reality in the series is actually only Hinata's dream state.
So fanfics, art and theories could have centered around how Team 7 was going to break out. And at the end of all the Hinata pandering to the NH/SS fans, Kishimoto could have cashed in on the NS fans with another mini version, movie, novel or one-shot anime special that showed the ending going in an entirely different direction. Obito's dream state gets broken, Team 7 prevails and wakes up, then NS and the hint of SK are shown before everything is returned to normal.
So the idea of alternate universes in Naruto could definitely be supported. Too bad Kishimoto wasn't creative enough to go that route.
That version of Kishimoto must exist somewhere else right now, along with a bunch of happy NS fans!! 