Hmm. I agree with this timeline too. But what if we put ORAS around the same timeline as XY? Both are Gen 6 and it would explain why Wally is still about the same age in S/M. In the other universe without the mega evolution, I guess R/S/E would be in the same time-frame as you put FR/LG but I think putting ORAS in Gen…

Well, I think it’s because of what’s in those pages than the number of pages. If you compare any given One Piece chapter to other regularised weekly shounen jump series, you’ll see that Oda packs every page with a shit ton of content, panels, text and characters. Maybe that’s why.