What Is It About General Relativity That Makes It So Useful?

General relativity has been investigated for 100 years, so we know the structure fairly well. At this point, unless there's something really special about GR that makes it more consistent than other things, I don't know if that's something you could say. One is the general conceptual structure, which I tried to outline. But also one should say that the theory of causal sets or even some other loops or strings is certain that well understood as general relativity and no work close to the experiments as relativity is. And then another level you can say, if you can add up, is that the static structure is okay but what you want to change is the dynamics of how this metric changes. This leads to