He's not missing important concepts but deferring important concepts to learn other important concepts that lead to progress today.
You end up paying back that deficit one step and one layer of abstraction at a time:
Some of Brian's biggest forward mental leaps came when he took
a step back away from the day-to-day project grind, learned new
concepts in a course or from a book, and then thought about how to
apply them to SwearBuy.