That was some sublime management right there, kind of sad that Square Enix lost that rhythm, otherwise we would've gotten Final Fantasy XXVII in 2027, like Deus Ex Human Revolution predicted.
I really do hope they switch to Hindu numbers rather than Roman at some point if they go that far. It's going to be awfully weird if we ever get to a Final Fantasy L. I actually had to look up what 50 was in Roman numbers, so I doubt I'm the only one that wouldn't immediately recognise FFL as FF50
I doubt they can get back to 3 mainline titles a gen, but 2 should definitely be possible. Especially if they use different teams for each of them, and don't have any screw-ups that require shifting all of their resources to something else *cough* FF14 *cough*