I expect it to be an upside down parabola. From my experience, top performers in school were either very smart or worked very hard, or both - two skills necessary for software engineering achievement.
The other side of the parabola are smart kids who worked hard on things they found interesting, which just happened to not be school
The very smart and very hard working are of course the shoe-ins. And then it's either the very smart and lazy or moderately smart and very hard working who are next most likely.
But the moderately smart and moderately hard working just get lost in the crowd.
The other side of the parabola are smart kids who worked hard on things they found interesting, which just happened to not be school