Made this comment below but spending billions on another collider in an attempt to essentially validate SUSY is irresponsible. A few years ago, a bunch of physical philosophers tried to justify this turn of particle physics in general away from experiment, particularly suggesting the search of symmetries and mathematical beauty (I guess) was enough of a justification for the work even though it essentially is contrary to the basic scientific principles of relying on experiment and observation. Now, we're seeing real world consequences of that mistake, billions in resources and potentially decades of man-hours to be devoted to another super-collider.
Honestly, this money could be spent on myriad other projects, not to mention towards fusion research or alternative energies (solar, wind) in general especially in the face of climate change. Again, seeing the failure of the LHC and then deciding you're going to double down is just straight irresponsible. I honestly wonder what member states are thinking when they see CERN contemplate this especially after the LHC failed to find SUSY particles.
This is just another painful reminder of how narrow minded some scientists are and so focused on their own little niche. There are so many larger problems the world is facing today, it's upsetting but not surprising no one at the table even asked the most important questions when making these plans, "is this even necessary?"
Last tidbit, there are next generation acceleration schemes using lasers that could promise much cheaper acceleration of particles on a much smaller scale (centimeters) although the brightness and general beam quality isn't quite there yet. That could be a potential route forward and be much cheaper in the long run, it just would require a) some time and research but more importantly b) the current crop of experimental scientists at CERN might find it not their expertise and so might not get the grants. Again, reiterating the narrow mindedness of scientists these days.