I think your interpretation is too charitable to Marcus' viewpoint. He made the analogy that deep learning practitioners are "looking under the streetlight" for the key to general intelligence. This means he thinks that deep learning itself is not sufficient to reach general intelligence, and there is some missing ingredient. This is a very strong claim, which I don't see any evidence for. Your comment suggests the opposite -- that deep learning may give rise to symbolic reasoning as an emergent property, that there may be no missing ingredient.

Personally, I'm agnostic. Deep learning may reach some sort of asymptote but it may be entirely possible to "build a ladder to the moon."