And one can speculate that the tardiness and wobbliness of humanity’s progress on many of the “eternal problems” of philosophy are due to the unsuitability of the human cortex for philosophical work. On this view, our most celebrated philosophers are like dogs walking on their hind legs—just barely attaining the threshold level of performance required for engaging in the activity at all.

I think there are two better explanations.

First, assuming that philosophical questions have answers, the tools needed to find those answers will be things like evolutionary psychology, artificial intelligence, statistics, linguistics, cultural anthropology, and not in the topics addressed in undergraduate philosophy courses. Graduate courses emphasize logic, which is better, but 20th century philosophy showed mainly how logic fails when applied to philosophical questions. Philosophers (or, to paraphrase Aristotle, "meta-physicists") should be meta-scientists, trained in all branches of science.

Second, as time goes on, we have to try harder and harder not to see the answers to the "eternal problems" lying in front of our noses, because we're still hoping to find different answers.