Norvig has written a ton of kick ass programs in his career that are concise, efficient, and correct, in much less time than most programmers would require.

Furthermore, even picking your own problems can be a way to achieve > 10x productivity, as identifying useful problems to solve is also a crucial skill.

I attended a talk given by Norvig, where he frankly admitted Google picked markets to enter where they could get good quality data to train their machine learning models on (this was many years ago). Maybe lesser developers wouldn't have that insight.