Well they believed they would see supersymmetric particles at older colliders as well. The problem now is that the Higgs mass anchors the valid range for "natural" supersymmetric models. Last I checked most of those where ruled out now. That still leaves the problem that the Higgs mass is unexplained. So the obvious step is to do Higgs precision measurements, which is what they intend to do with electron-positron colliders tuned to the Higgs mass.