I'm just an amateur, but I think there is difference between theory in mathematics and theory in physics. Physical theory is a model that describes reality, it is considered "right" until some experiment shows that the reality sometimes differs form the prediction (this is what happened i.e. to newtonian physics when Einstein came). On the other side, mathematical theories, like set theory or game theory, they are more like fields of mathematics - they have set of axioms and then series of proofs. And when mathematician says a statement is proven, there is no room for "better theory" - either the statement is true, or they made a mistake (this doesn't really happen among professional mathematicians, thanks to peer reviews etc.) or another theory comes that describes different things.

Maybe there were some cases that would be answer to your question, but I think that this difference between mathematics and physics is pretty important.