It seems likely to me that some arrangement of nerves is possible that's comparably complex to ours, but does not produce consciousness. (I dunno, maybe some organism with much more complex sensory organs than ours that devotes so much complexity budget to that that it only has enough left to devote to general cognition to give it the intelligence of a mushroom, who knows). In other words: I suspect complexity is necessary but not sufficient for consciousness to occur. I don't think that takes away from your suggestion that consciousness in AI systems is _possible_, but I don't think it's the case that it's an inevitable outcome if only we can make our systems sufficiently complex. There's probably something about the specific structure of the complex thing we'll need to master as well.