The particle physics desert theory states that all fundamental particles have mass less than 1 TeV or greater than 10^13 TeV. There is a desert between 1 and 10^13.
Can this theory be tested without having to test all the way up to 10^13 TeV? If one has to do that, the theory is useless. In particular, can the theory be proven correct (a weird thing to do to a theory) by only testing up to 1 TeV?
What is the nature of inflation, neutrino mass, dark matter, and dark energy? Assuming the desert theory is proven true, will the answers to these questions definitely be found before 1 TeV? Or, if the answers aren't found, will we definitely know we will not be able know the answers until we can build (at least) GUT-scale particle accelerators?
Of course, astronomers can observe relics from when the universe was at GUT-scale energy to try to answer these questions.