For example, I would put forth that for a given problem, there is a lower limit to how simple you can make divided pieces of that problem. You can't compute the trajectory of a thrown baseball using only a single transistor. Granted most problems can be divided into incredibly simple steps. The question we face is "is AGI reductive enough for human beings to create it?" Is the minimum work-unit for planning and constructing an AGI small enough to be understood by a human?
That's of course putting aside the problem of scale. The neocortex alone has 160 trillion synapses, each of which exhibits behavior far more complex than a single transistor. You could argue that for many commercially-viable tasks we've found much better ways than nature, and that's true, but AGI is a different game entirely. Our current AI methodologies may be as unrelated to AGI as a spear is to a nuclear missile despite them both performing the same basic function.