The plight of evolutionary theories is that of the ‘unknowable’, a situation that resembles the Kantian theme of the noumenal. That in turn may only be Kant’s approximation to the veiled aspect missed by most theories. Look at the Axial Age: it is complex of five plus separated regions to be observed in enough detail to account for the effects over many centuries. That’s almost impossible. And even as you zoom in the noumenal aspect throws the key out of focus.
If you wonder why the evolution debate can’t settle down, check out WHEE at history and evolution.com: The observation problem is compounded (in history) by the need to observe dynamical transformations of civilizations over millennia. The problem of causation is compounded by the needed to account for free will, or, at least, free agency indetermination. The causation problem is also bound up in the need for ‘causal factors (analogous to fields)’ that can act over a region, and effect multiple subsectors of that region (read: a time-slice of a culture in time, and the culture factors involved: history, biographies, politics, arts, etc…) The latter problem puts the problem far beyond primitive human sciences. What does this ‘cultural evolution’ have to do with earlier organismic evolution? There are obvious distinctions, but the basic situation of a group of hominids and their context (culture) is simply an elementary version of a whole civilization. Evolution can’t just act on organisms and their genetics: it must operate on a tandem combination of organisms, their behaviors, and their group dynamics. We have no real idea how that works. But the Axial Age might give a hint: something stupendous in scale able to operate globally over separate regions in the gestation of civilizations, cultures, and their detail. We are so far outclassed by the reality of evolution, or so we suspect.