It is ultimately a hardware problem. To simplify it greatly, an LLM neuron is a single input single output function. A human brain neuron takes in thousands of inputs and produces thousands of outputs, to the point that some inputs start being processed before they even get inside the cell by structures on the outside of it. An LLM neuron is an approximation of this. We cannot manufacture a human level neuron to be s…
Like you mention, each individual neuron or synapse includes fully parallel processing capability. With signals conveyed by dozens of different molecules. Each neuron (~86 billion) holds state information in addition to processing. The same is true for each synapse (~600 quadrillion). That is how many ~10 Hz "cores" the human computational system has.
The hubris of the AI community is laughable considering the biological complexity of the human body and brain. If we need anywhere close to the same processing capability, there is no doubt we are multiple massive hardware advances away from AGI.