"The Nobel prize judges have always been sticklers for experimental proof." One of the big challenges of devising a grand-unifying theory of everything is that

"The Nobel prize judges have always been sticklers for experimental proof." One of the big challenges of devising a grand-unifying theory of everything is that, if it doesn't make different predictions than existing theories do in any context, it's experimentally unverifiable. We can hope for a unifying theory that makes everything simpler, but it's far more likely that a theory that deals with all things at once will makes dealing with special cases harder. If such a theory is harder to work with and does not differ from special case theories that are easier to apply, why bother? Of course, a unifying theory probably will differ from existing theories in at least some contexts. They may be extremely high energy, gravity, etc. contexts that are beyond our current technology to test. String theory likely falls into this category. The question is, how much resources should we pour into developing a theory before demanding that its differences with currently accepted theories become testable? Quite frankly, answering this question is above my pay-grade. Scientific history is full of both dead-ends and things that were initially thought to be useless that have since become the foundations of entire fields. How do we know which string theory is? If we cut funding to string theory development, are we cutting off a field that will one day be essential? By continuing to pour funds into string theory, are we funding a dead end and starving several other things that might have been revelations?