I don't think he'll go either, in fact I don't think he'll go even if we drop out of top 4 but that is more to do with Wenger not wanting to go and the board being happy with him meeting their requirements, a season out of CL won't be enough for them to drop him.
So far this season is not that dissimilar to last season in as much as we've never really truly challenged for the title...if it finishes as it did last season I have no idea how Wenger can justify that he is moving the team forward, his words were that he will only extend his contract if he believes he is moving the team forward.