> I mean, the LHC is certainly a significant achievement, but compared to the detection of gravitational waves or even just exoplanets it doesn't seem to deliver as much bang for the buck.
Well, first, LHC was "unlucky": they could have observed a lot of new particles if they would have been there. It feels unfair to say "this experiment that looked at X and had 50% chance of seeing something was a waste of money because they haven't found anything, this experiment that looked at Y and had 50% chance of seeing something was not because they saw something": both experiments are as worth a try. LHC still have observed the Higgs boson, which is still quite a big thing. LHC has also constrained a lot of theories (seeing that a particle predicted by a given theory is not there is very useful scientifically).
But more importantly, I have the feeling that the notion of "bang for the buck" is pretty different from a scientific point of view and a layman point of view.
For example, you mention exoplanets. Scientifically, those are really not a big deal. We already know that planets can exist, there are 8 around the Sun, so finding others around other stars is really not a big deal: everybody was expecting them to exist and knew the only reason they were not seen yet was the limits of the technology. One could even argue that using money to detect things that are pretty trivial is in fact the worst delivery of bang for the buck. Don't get me wrong, this is still nice to see them, but it's the same level as pentaquark (discovered at LHC).
It is sometimes surprising to see the public/media reactions to discoveries. I'm still not sure why layman people were so excited about gravitational waves but not much about the tau neutrino.
