Horror, like pretty much everything else, will ebb and flow. It's all about our collective mindset and perception of the world at any given time. Generally, times in which things seemed grim (for example, say World Wars I & II) have seen increased output for horror due to the generally dark or fearful mood. This is such a time in the world right now, so according to the trends of the past, we should be seeing a high point in the genre (and, like you said, it seems we are getting there).

And, sure enough, sometime in the future it's all going to suck again.