"Why three families ? Why the particular symmetry structure ? [...] If the Higgs particle turns out to exist as conventionally described, with a reasonably low mass (say less than 200 GeV) then that closes the Standard Model from a mathematical point of view. It is then quite conceivable that new physics, not contained in the Standard Model, will be way beyond the reach of any accelerator imaginable today. In this case, humanity might never get an answer to the questions posed above."
M.Veltman, Reflections on the Higgs System (1997).