I do not believe this is so.
I feel that the Pareto principal is a direct result of the bell curve.
To do anything well, you have to have passion.
To do anything well, you have to put in much practice.
To do anything well, you have to have a natural talent for it.
If you have passion, natural talent and really practice at something you are much, much, much better than everyone else at that thing.
If you take the opposite people, it doesn't matter which parts they do not have, they are equally bad compared to the best. Or, basically, make up the long tail
Basically, a few above average attributes puts you head and shoulders above the crowd.
It is very easy to get to 80/20.