The author mentioned bicycles and inadvertently missed an opportunity to show another "unknown reality" that beautifully illustrates his point.
Consider typical adults (not physicists) with 20+ years of bicycle riding. If you ask them, "how does a bicycle turn?", they'd respond that "you just lean into the direction of the turn and it turns."
But that's not the complete picture of what actually happens.[1] If you were to capture the bicyclists with a high-speed camera, you'd notice that there's always a micro movement of countersteering to make the bike momentarily lose its balance and "fall into" the turn. Then there's an immediate correction of the steering to match the turn. This all happens in the span of milliseconds.
Even though the human body "discovered" the countersteering by way of kinesthetic feedback, the bicyclists' brains don't explicitly communicate this intermediate step to others. (Tacit knowledge.[2])
It's not always the case that we "simplify" reality for innocent purposes of pedagogy. (E.g. we tell "lies" to children about "numbers", "functions", etc and as they get older, we successively remove the layers of lies as they get into high school and college math.) Instead, we often don't even know the reality (e.g. bicycle countersteering) to consciously omit it.
That extra reality may not even be important. If one human is teaching another human, you can leave the "countersteering" detail out and it won't matter. The 200 years of people learning how to ride bicycles is evidence of that. However, if you're a robotics scientist and want to build a self-driven motorcycle, the reality of countersteering becomes a crucial detail.