The almighty Seth Godin says: "In every category, in every profession, half the people are below average.".
Bzzt! Wrong! Na-ah. Half the people in any industry are below the median. As in, half the people are below the half-way point (which is what the median is).
But I still think his main point is right. Let's fix the math.
In any industry you're going to have star performers. Programmers ten times better than the rest, etc. We all know the cliche. That drags the average up and beyond the main group of code-monkeys or office-slaves or whatever-you-call-your-grunts. And it drags the average higher than the median. Ability is a skewed distribution:
So Seth's argument about marketing to the below average applies even more he realises. More than half of the people in any industry are below average.
But there is a counter-point: the average is a lot higher than you think. Most jobs look easier on the outside than on the inside. Assuming you are more clever than most people is a dangerous game.
As for me, hey, I'm with the huddled masses. Who wants to be a Distinguished-Engineer anyway!