"Only you know I'm the creator of Bitcoin, don't tell anyone. I have a billion dollars worth of bitcoins, but I can't use them until 2020. That's why I need all your money for this Bitcoin Bank. You can trust me, I'm already a billionaire."
That would explain why he created fake evidence in 2013 but kept it secret. This public exposure could have come from his over-excited investors, or maybe he's throwing his net a little wider to see how much more he can get before it falls apart.
This is certainly possible. The data so far indicates one of the follow is true.
1) Craig Wright is Satoshi
or
2) This is a conspiracy involving multiple individuals in different countries trying to convince us that he is.
or
3) This one of the longest cons ever and Craig Wright started laying the groundwork to convince people he was Satoshi back in 2013.
Personally based on the information presented in the wired and gizmodo articles I lean towards #1 lots of compelling circumstantial evidence there. However #3 is not impossible especially if you can establish a definite profit motive for setting up such a fraud in 2013.
Or 4) he is seeing stuff. He might have lost his mind somewhere during his life and actually believes he is satoshi..
It probably happened in 2013 when he started laying the foundations to prove his claim.