I'm not sure what your point here is exactly. Versus got "greenlighted" on a conceptual level (i.e. "Nomura, go make an action FF") in 2005. Even if the plan was to release this title years and years after FFXIII (and again, I doubt very much this was the plan), everything was in place to do a thorough preproduction push with a small team. SE had working PS3 technology (whether or not it was suitable for a final release) which could've been used to build a vertical slice. A languorous process over three years should have been plenty of time to extensively plan the game, iterate on basic gameplay loops with a prototype slice, and otherwise prepare the game's core design so that it could ramp up into proper production quickly and efficiently.