I understand the logic for GUT, proton decay, SU(5), SO(10) manifest at extremely high energies, as well as SUSY-extensions, has it been ever seriously considered that GUT is unrealized in nature? Fundamentally new physics takes over at higher energy, and therefore SM 200 Gev level energy decouples at GUT-level 15 TEV scale? Proton decay and mangetic monopoles and SUSY have not yet been observed. If GUT is false, how would this alter our understanding from Big Bang to particle physics? If GUT is wrong, are there serious alternative proposals for 10^14 GeV scale physics?