I would say there is something about the ability to more quickly grasp subject matter that seems to be related to IQ (barring a second E). I see this in the people I work with, maybe that's showing their processing speed, but it seems to correlate with intelligence. These people are the ones who will get to the answers or core issues more quickly than most employees. This can be very subject specific (i.e., one person figures out a quantitative issue fast, another person pinpoints a training gap quickly while others are still working to understand the situation).
That said, it doesn't mean that others don't do very, very well. It's just that one group of people thinks at what seems to be a different speed. Mix the latter with a low work ethic, and they won't succeed. Mix that ability with a good to strong work ethic and they stand out.
I also agree with Howdy's point on success definitions varying widely.
