Since the lack in presentation of the Thread of 10023213 I had to open a new one. I'm sorry if you are insulted by this as spam, but I can't help it. 
At first I want to mention the fact, that many favorise dead people (like Obito, Mardara or Izuna) to be tobi, and only a few can speculatively explain how that could have worked out.
And that's the problem with this theory too, we saw the So6P on his deathbed. BUT we are talking about the Sage of the Six Paths. It is possible, that he just gave birth to and ran away from the responsibility. (Yeah, the second part is a joke.) The point is, how he did it is fishing in the dark and rather pointless. He was high likely capable of doing it, that's all that matters.
Why the So6P did what he did:
The Sage wanted to bring Peace to the whole world. He invented ninjutsu to make the world to a better place. If you where in his position, wouldn't you want to know if your plan turns out well? Wouldn't you want to know if the world is this place you have dreamed of? Of course not ... ^^
So he stayed and that also explains why tobi was never mentioned in the beginning of this shinobi world. He kept still until ...
Why "Tobi" did what he did:
... until he realizes that this shinobi world will never turn out as a peacefull world. So the Moon's Eye Plan took his place. If you think about it, the Moon's Eye Plan is the So6P vision!
Why is the So6P Tobi?
For one reason. To beat Edo Madara. Many came to the conclusion that Edo Madara must be close to the So6P level. So who should beat Edo Madara? Naruto? Sasuke? Don't be ridiculous
Tobi also possesses, like the So6P, the Sharingan in one eye and the Rinnengan in the other. (Thanks to 10023213 for that!)
So ... I'm pretty sure he is Tobi. File closed.
(Sorry, had to do it^^)
And thank you for reading even though the post had no pictures in it.
At first I want to mention the fact, that many favorise dead people (like Obito, Mardara or Izuna) to be tobi, and only a few can speculatively explain how that could have worked out.
And that's the problem with this theory too, we saw the So6P on his deathbed. BUT we are talking about the Sage of the Six Paths. It is possible, that he just gave birth to and ran away from the responsibility. (Yeah, the second part is a joke.) The point is, how he did it is fishing in the dark and rather pointless. He was high likely capable of doing it, that's all that matters.
Why the So6P did what he did:
The Sage wanted to bring Peace to the whole world. He invented ninjutsu to make the world to a better place. If you where in his position, wouldn't you want to know if your plan turns out well? Wouldn't you want to know if the world is this place you have dreamed of? Of course not ... ^^
So he stayed and that also explains why tobi was never mentioned in the beginning of this shinobi world. He kept still until ...
Why "Tobi" did what he did:
... until he realizes that this shinobi world will never turn out as a peacefull world. So the Moon's Eye Plan took his place. If you think about it, the Moon's Eye Plan is the So6P vision!
Why is the So6P Tobi?
For one reason. To beat Edo Madara. Many came to the conclusion that Edo Madara must be close to the So6P level. So who should beat Edo Madara? Naruto? Sasuke? Don't be ridiculous
Tobi also possesses, like the So6P, the Sharingan in one eye and the Rinnengan in the other. (Thanks to 10023213 for that!)
So ... I'm pretty sure he is Tobi. File closed.
And thank you for reading even though the post had no pictures in it.