Chaotic nonlinear dynamics have been an object of mathematical research for a very long time and we have built up good mathematical tools to work with them, but in spite of that turbulent flow and similar phenomena (brains/LLM's) remain poorly understood.

The problem is that the macro and micro dynamics of complex systems are intimately linked, making for non-stationary non-ergodic behavior that cannot be reduced to a few principles upon which we can build a model or extrapolate a body of knowledge. We simply cannot understand complex systems because they cannot be "reduced". They are what they are, unique and unprincipled in every moment (hey, like people!).