I agree that known biases can be explained by curves like those, plus the choice of a "frame". But how do we know we're not overfitting?

In other words: does prospect theory pay rent?

I'd want to at least see that we're identifying some real differences between people when we fit their curves from a bunch of measurements of their behavior - I'd expect their personally fit model to describe their (held-out from fitting) future actions better than one fit over the whole population, etc.

It seems like the additional degree of freedom "well, it depends on how they chose their frame in this instance" needs to be nailed down as part of testing the model's fit on future actions.