Could a game programmer ever achieve mastery? I guess that even if you work like 5 years in a domain (like the physics engine programmers for a modern FPS), how can you say that you are an expert in Game programming,when, for example you can't do the graphics part, or the structural organisation part? For me, everyone has room for improvement.
Let me give you one of Bjarne Stroustrup's quotes: "People who think they know everything really annoy those of us who know we don't". For me, the quote suggests that he acknowledges the fact that there is always room for improvement.
Meh, my opinion is pretty fixed, and i would never say that I am an expert even if at 60 years old i would have invented some awesome algorithm that produces pizza from my own programming language code. Especially if a teen comes to me with his own language that would give me soda with a while(1) loop.