I think the reason why it has dropped in ratings is because of the long time between showing new episodes. Why wait a month before continuing? This kills many shows when they go on hiatus for so long . People move on very quickly and go to the latest new thing; The Voice, etc. Besides they have spent to many episodes not tying the story together fast enough. We figures out where they were going before the break, but most people want it spoon fed to them so it is easy to comprehend. Unfortunately Fringe makes some people think too hard . Too much work , so they move to something more easier to get ,wrapped up in a 60 minute episode.