I'll second this one, and take it even a step further. I worked in academia for a while, surrounded by our (and other) nation's brightest scientists. As a general rule, they were indeed brilliant. But there was also a large group of people with MD's or PhD's who were just friggin IDIOTS. I mean no common sense whatsoever, no ability to function in a normal way. But they got good grades in school, didn't they! Maybe even went to a school for the gifted because they were so 'smart'?
Which brings me to the second point- I bet if you were to track the success (don't ask me how to define success, use your own definition) of average people vs the 'smart' ones you might be suprised. I doubt very much it would be skewed towards the smart ones. My personal theory is the smart ones know what they are in for so don't try and take risks they feel are unacceptable. The less smart just go for it, and sometimes succeed in a spectacular fashion.
2.4 statute miles of surgical tubing at Yale U. = 1 I.V.League