You might think that mastery on a subject comes from having massive knowledge in a subject.
Massive knowledge is like local cached database. It is just pure information.
Mastery is about using this knowledge to maximize deduction while minimizing incoming information. In other word : awareness.
In an age where we suffer information overload, the true master is the one that percieve whispers and can tranform them into wealth.
I finished Reversing lately, I see the same assembly code than the author, but he is capable of deduce lot more from the very same information. I might say : from less information, because he is able to filter noise better than I can.