Interesting essay. Makes some very good points, however I have to disagree with this one.

> ... they keep some sort of overall concept of learning. This is a pretty god-of-the-gaps-ish hypothesis, and counterbalanced by ...

The author is really missing the obvious here. Learning difficult subjects fundamentally changes how you think about and approach things. People aren't born able to engage in critical thinking or being able to reason algebraically or with an ability to navigate formal logic. That doesn't mean school is the only way to impart such skills, but it is certainly one of the ways.

Of course if the metric you use is "ability to answer trivia" then you are going to fail to capture that aspect.