Physics Today seems to have decided to deal with Sabine Hossenfelder’s criticism of a future collider by publishing the least credible possible response: a column by Gordon Kane arguing that string theory predicts new particles of just the right mass to be likely beyond the LHC reach, but accessible to a higher-energy proton-proton machine.
In the column, we learn that:
In recent years there has been progress in understanding those [string theory] models. They predict or describe the Higgs boson mass. We can now study the masses that new particles have in such models to get guidance for what colliders to build. The models generically have some observable superpartners with masses between about 1500 GeV and 5000 GeV. The lower third or so of this range will be observable at the upgraded LHC. The full range and beyond can be covered at proposed colliders. The full range might be covered at a proton–proton collider with only two to three times the energy of the LHC. One important lesson from studying such models is that we should not have expected to find superpartners at the LHC with masses below about 1500 GeV.
Kane has a long history with this kind ...