I don't disagree with your point about neuroanatomy. But it may well be that true AI is possible via some avenue other than emulation of existing biological intelligence.

As for "DECADES" -- that is a pretty short time, when you have a very large and important research programme ("Friendly AI", some call it) to carry out. If we postpone this research some decades, and then someone makes a breakthrough in AI without ensuring Friendliness, it could be bad news.