Exactly my thoughts: neither of the two characteristics ("exceptional-ness" and "loyalty") are binary qualities. Both exist on a continuum, and more importantly, they're orthogonal. But the article assumes everyone is either moving up or moving out.

What ABOUT the really good engineer with a family, who's content to stay even if the work isn't bleeding-edge exciting? Are they ignorable just because they don't fit into this model? Do we stigmatize them because they're neither churning nor making partner?