Sorry, but you two are wildly underestimating the scale of the project here. You just have to look at the map and remember that the entire first part is set in the little black circle on the Eastern continent:
Or, y'know, that it's an entire planet. Just think about the number of unique locations and the size of the traversable space that we got in FFXV (that is, not much, with only 2 open towns), and about the approach of major expansion that they've shown so far. Even with next-gen exclusive SSD loading and AI-assisted development techniques, the idea of building such a huge - and, more importantly, VARIED, world - in a single game is highly unlikely, especially when the whole point of making multiple games is to spread the work around to make the project more feasible.
They might surprise me, but I think we're probably looking at a 4-part saga here. The exceptionally massive Kalm-To-Northern Crater act needs to be two games, and I think a good mid-point would be Nibelheim. It's right around the middle, and gives the second game a nice setup where you start with the flashback to Nibelheim's destruction, and end with the massive WTF moment of arriving to find the town (seemingly) perfectly fine and intact.
