It's like doing a car crash safety simulation and stating that the airbag provides protective force "linearly proportional to the force of impact, with alpha > 1" ... without ever measuring it or doing any calculations on why this would be the case. Would you drive in a car that was tested this way?
I'm not saying either that this phenomenon never happens. I just think it's rather rare, especially among sensible and skilled economists. See also the great Bob Sugden's paper "Credible Worlds", which is available here at the moment.
https://www.researchgate.net/profile/Tony_Lawson2/publicatio...
I hate to be the one to say this -- but most of modern economics is crap, given how reflexive it is. People know how the fed acts -- they know how policy makers act. The models don't take into account this reflexivity.
Someone like George Soros is a thousand times more savvy on how the economy works than post-docs publishing econometrics papers for $40k a year.