As if there was something other than the laws of physics preventing natural selection from testing smaller structures.
Or that there’s something (other than the demands of the computation itself) constraining the architectures that were tested through natural selection.
Likewise manmade models based in mathematics and statistics have long proved more accurate in predicting outcomes than the human mind, even though we know the mind doesn't employ math.
Human-made machines have made it possible for elephants to fly. Nature never will.
There is. Anything that can't be reached by a small number of genetically small steps that either enhance or at least maintain fitness will never be reached.
I think the best story for understanding circuitry in vertebrates comes from the work on hierarchical pattern generators -- where much of the work was done on lampreys.
Grillner, S. (2006). Biological pattern generation: the cellular and computational logic of networks in motion. Neuron, 52(5), 751-766.