If the seemingly fine tuned values in the standard model parameters (19 or so of them) don't have further derivations. Let's say there were just inputted by design. Do you still consider these beyond standard model (or called them) as naturalness? or simply fine tuned? or fined tuned naturalness?CEPC can measure the Higgs mass more precise but the dominant uncertainty for the vacuum stability question comes from the top mass where CEPC won't contribute. SppC might help with it - not clear how much, the LHC will make very accurate measurements already.
Unless one of the machines finds something completely new they won't help with the hierarchy problem.We don't know if such a collider will be built in the future. There are some people working on some critical concepts like the cooling at the moment (MICE).You can never be sure that they are not composite, but it is quite unlikely already.
Whatever, it would then officially be the end of physics where we literally won't know furthermore. Is it not?