I don't really know to be honest. It does make my heart a little sad to know that it may be it, no more hype over the new games. Although I think it was the hype, that led me to feel ultimately somewhat confused and disappointed over the new games. I just found it too complicated, don't get me wrong I love the game, simply for the theories and Spring-trap But I just found it quite complex and somewhat confusing, I didn't like the hallucination part of things I did however like the ending parts, and the little mini-games.
I guess they could go back even further, to the first ever restaurant.