Don't mean to be pessimistic, but I think it will get worse.
The new age of technology has made terrorist acts very likely to be filmed on mobile phones/cameras and instantly uploaded and shared between millions on the internet (or even streamed live).
according to scientists, there will be day/days (I'm not sure) where we, humans, can't use any kind of technology. it will be dark.
so I think on that day, there will be no terrorism. I mean, how can people do terrorism while they need to keep alive in that situation. IMO