To trot out some theoretical evolutionary support, only extremely basic extrapolation would be required in the ancestral evolutionary environment. [....] Being able to produce simple chains of cause and effect would confer a significant survival advantage, but you wouldn't need anything more than that. The world was simple enough that we didn't have to deal with complex interactions - linear extrapolation was "good enough". The world is much different and much more complex today, but unforunately, we're still stuck with the same linear extrapolation hardware.

The world was simple then because we hadn't evolved greater predictive ability, not the other way around. It's more complex today because humans have used their predictive abilities to build complex tools and social structures. So our extrapolating hardware is correlated with the modern world in two senses: it was enough to build it, and it is enough to presently survive in it.

True, we would profit greatly from better extrapolating hardware. But this was just as true in the ancestral environment! Extrapolation ~~ Intelligence ~~ Power to achieve goals. Also, better hardware gives a particular advantage in intraspecific competition, so once genes (or other replicators) for it appear, they spread rapidly.

Ours is not the narrative of "how humankind barely had enough brains to cope with the modern world". It's the narrative of "how humankind had just a tiny amount of brains more than he needed to cope with his ancestral environment, and used them to build a world so complex that only he could survive in it, to the exclusion of cousin species and of older human genotypes".