[ravi-delia]

I'm most of the way towards agreeing with you, but I think you underestimate how far you could get without any major changes. Most of the brain consists of feed-forward processing, and what closed loops exist are probably replacements for backprop rather than essential to cognition. That's all the low level processing, from visual to motor. Now obviously we have higher level processing too, and it might be super weird! But no model we've made comes close to the size of even specialized brain regions, and study after study has demonstrated the power of the subconscious mind. Once we have big enough models, we might find out that all we need to take it to that final step is a while loop.