> You make a good point - without the expensive accelerator data, we’d have no idea that these omg ridiculous stupid waaaa predictions are true or false!!!No, even with the accelerator data we probably still won't be able to conclusively rule out many approaches. We'll only be able to rule out overly specific variants of those predictions. Which, given the infinitude of available theories, doesn't do much to narrow things down.
Think of it this way: At one point, geocentric theories of planetary motion based on nested crystal spheres were requiring ever more elaborate arrangements with more spheres. More observations with greater precision only required adding more spheres.
We're somewhat in the same situation WRT high-energy physics today, in that larger and more powerful accelerators will only rule out particular theory variants, just as more powerful telescopes would only have ruled out particular arrangements of crystal spheres. Just as geocentrism as a category of theories isn't falsifiable by greater precision, many of the current approaches toward HEP aren't falsifiable by ever more powerful accelerators. You can always add another dimension or mathematical elaboration to explain the observations.
Which simply means that right now, another large particle accelerator probably isn't the most useful experimental approach to figuring out how to reconcile the two well-supported theories we do have.