Here’s a question I have that maybe somebody in this thread can help me with: what is the positive case for a new particle collider at much higher energies than the LHC?

It seems to me that particle physics post-LHC is just the same as it was pre-LHC. We verified the existence of the Higgs, which is great, but that meant no revisions to the Standard Model were needed as it already assumed the Higgs. And no exotic or unexpected new particles have turned up.

You can definitely argue that the technology spin-offs from the LHC have been great; but is that really an argument for another collider specifically, or just Big Science in general?

To put it another way, what’s the argument for a collider that goes beyond “provide employment for hundreds of high-energy physicists, and throw some unprecedented engineering and logistical challenges at then”? Is there a pitch that’s based on the science rather than the technology?