Inferior at maintaining civilizations, economies, and social systems that promote justice and meritocracy. Inferior at advancing science, technology, and the sum of human knowledge. While you could certainly make the argument for a separate underclass/undercaste race of dark skinned landscapers, farm workers, and construction workers, many of those trades are so advanced today that they'd still need eugenic pressure to improve their average intelligence to be made useful for such a position. Whether they'll realize it's in their best interest to accept that eugenic help or not remains to be seen.