Earlier quoted context omitted.
This isn't starting tomorrow. This is going to take 2-3 decades, starting with a design study. So part of the point here is future-proofing. Upgrades to LHC are due to take place. We don't know what the outcome of experiments after those upgrades will be. We don't know where other research will get us to over the next decade or two. If we want a new collider in place 3 decades from now then it is time to start planni…
I take you're point, but this is all still entirely speculative as far as I can tell. Do we need it now? No but we might in 30 years! Or we might not. And there is no good reason to think we will. Particle physics has felt very tapped out for a while. And we still have the LHC and LHC upgrades to answer the few questions left Remember.
CERNs yearly normal budget is ~$1.2bn. Spending a few million on design studies and planning now is a pittance as risk mitigation against delaying future experiments.
Once there's a need to commit serious cash, then these questions needs to be answered.