I completely agree with it being an investment for the future. But not that the limits of building more powerfull machines are far from reached. The LHC works with extremely high levels of energy. To build a new supercollider that would be only 10% more powerfull would make no sense at all. The next generation supercolliders would have to be in a whole new scale of energy levels and this means that with the next generation supercolliders the limits to how far you can go are in sight. because the next level after that would have to be in a whole new scale as well. So if each new scale would mean you would have to multiply by four, or something similar, that within only a few generations you would have to build a collider as big as switserland itself. But it's not even like that, because the higher the energy levels, the more you would have to multiply your investments with.