No excellent answer pops into my head, which means I have to look into it more deeply.

One might think that 70+ years after the emergence of a General Theory apparently adequate to the task of explaining a complex economy, and which, by extension, should serve as the foundation of computer based models of the economy, that the failure of the field of economics to provide such an updated theory says something fundamental about the nature of the discipline and the great majority of its practitioners---and that what it says is not flattering.

Three questions present themselves:

1.) Were an updated General Theory capable of making verifiable predictions about the international economy developed and written so that it stands alone, without requiring prior understanding of Keynes's General Theory, generally be used as a text for macroeconomics in undergraduate and graduate courses?   (i.e., would it be commercially viable?)

2.) Could such an updated General Theory be used, (or have such updated theories been used), to generate computer based economic models with significantly more predictive and explanatory power?

3.) If, as seems likely, both 1. & 2. could be done, what does the fact that they have not been done show?

Historian Christopher Hill, in describing the reluctance of the Puritans to execute Charles I, proposed that there had been a "mind stop" in place that made a necessary step unthinkable.  Is that what is happening here?  Would production of such a theory and creation of such a model make the author such a pariah that no one is willing to do it?

Just asking? :-)

As the Dutch said while fighting the Spanish: "It is not necessary to have hope in order to persevere."