There ought to be millions of civilizations in the galaxy sending out radio signals. We don't pick any up. Therefore civilizations are probably short lived rather than long lived.
We don't really know where the bottleneck is in the Drake equation. (If you haven't heard of the Drake equation, it's an equation used to estimate the number of civilizations in the galaxy that are capable of communicating with us. The equation is basically correct, but we have no idea what the values are for most of the parameters. One of these parameters is the average amount of time that a civilization remains capable of communicating.) Using "reasonable" estimates people have come up with a lot of different values.
It's possible that the apparent small number of civilizations out there is due to civilizations being relatively short-lived. It seems to me that another strong possibility is that there's a bottleneck in going from "life" to "intelligent life." If I recall correctly, life on earth seems to have appeared not too
long after the planet cooled enough to make it feasible, but going from single-celled life to multi-celled life took 2 or 3 billion years. (I could easily be wrong about this.) So there may be a lot of planets with life, but very few of them where that life can be seen without a microscope.
As for the end of our civilization, I don't think the LHC can do that. My money is on out-of-control self-replicating nanobots. :-)