Two things are going on here:
- A setting with major races will generally stabilize on five. Less than five is too few, more than five is too many, either exerts pressure fiveward. Note that a setting can have any number of minor races without affecting the pattern of major races.
- The race archetypes themselves have have something like a Zipfian distribution of popularity. The Evil Counterpart split is a distraction here.
Fantasy and sci-fi have approached the idea of major races from different directions. Sci-fi produced the Proud Warrior Race
, the Proud Merchant Race
, the scientific Proud Scholar Race
, the mystical Proud Scholar Race
, the Green-Skinned Space Babe
, etc — which can each exist without the others. Fantasy, on the other hand, approaches it from the set, and how they interrelate — which can follow naturally from the idea that the races always shared a planet. Thus, each has something to learn from the other. While the sci-fi side can be short on interrelation, this is the fantasy side, which can use more about the archetypes.