My worry isn't addressed by this study: Some portion of people with dark personality traits start from a privileged position.
If someone's parent is the head of a company, or even well-connected, "achiev[ing] less and [being] considered poor team players" are much less of an impediment. If someone can effectively skip or get more slack in passing through the career levels for which dark traits are a disadvantage, they'll likely do quite well once they're at the top.
Exactly. A vague and general population study just tells is that dark traits are on average not helpful, it doesn’t tell us anything about outliers.
Someone with dark traits and significantly above average intelligence, or inherited wealth, may be able to avoid the pitfalls that otherwise prevent such people advancing.
Even if such people are very rare, e.g. 1 in 10,000, they would have an outsized influence, so we should be as interested in the outliers as the general population.
If someone's parent is the head of a company, or even well-connected, "achiev[ing] less and [being] considered poor team players" are much less of an impediment. If someone can effectively skip or get more slack in passing through the career levels for which dark traits are a disadvantage, they'll likely do quite well once they're at the top.