It's reasons like this that I don't necessarily see LHC or whatever rev of it as a problem per se. If the technologies developed to get there pay back the cost of the collider then it could end up being a very expensive toy and I wouldn't care. To me it's about the journey and getting there, because for big science in many case the real science is not the tool produced at the end but the science and engineering that has to go into making that tool.

Thus the question I have to the scientists pushing for a new LHC is: "What would we get from the journey?" If they truly believe in the project they'll have a dozen technologies that need to be developed to make their project happen, all of which have practical applications beyond their experiment. If they don't they'll just be pushing for "same but larger" which is IMO a waste of resources. Because why shouldn't we be investing in the technology to do "Same but smaller" in that case so we can do more with less?