It makes sense as he seemed to drift towards making the series a little bigger than it was before, if that sounds right?
Like before it seemed like Luffy becoming the PK was the end goal, but now it's a little more than that due to the Joyboy and Nika prophesies, along with Luffy having another dream that seems to come after he's the PK.
It's just a matter of when Oda decided to shift from having the PK dream be his main thing to having this other stuff happen.