Jayme's theory depends on trade emerging post-Bronze Age collapse of a sort that requires a new kind of theory of mind and processing in a low trust environment driven by international trade. The Ea-Nasir letter was written c. 1750 BC shows that the same issues were already around ~ 800 years earlier and there's lots of international trade going on even in the 3,000s BC. The content of the Ea-Nasir letter and the personal reflections and issues presented there really destroy the central thesis of the book. It's also got a few other serious historic flaws (false claims about the existent of omens ignoring previous examples thousands of years earlier) that make it the kind of book that's interesting but without question also completely wrong in its central thesis.