It seems to me that people are arguing whether Nature or Nurture leads more to success. The obvious answer is that they both matter. And the definition of “success” is a factor as well. Ex: In a physical fight, an untrained, large person is more likely to win vs an untrained small person. But a trained small fighter as a better chance against a larger untrained opponent. Yet a larger trained fighter will have the advantage over a smaller trained opponent. That is a classic example, but it limits the variables to 2 factors: size and skill. But obviously experiences play a role, as well as context. A trained boxer would have an advantage against a mixed martial artist in the square circle, but be disadvantaged in the octagon. Different rules define how “success” is measured.
Arguing about race and culture/sub-culture is basically trying to compare Nature vs. Nurture. Charlie Pride is a successful country singer, Eminem a successful rapper; Which was more important to their success? Their race, or their immersion into the respective music cultures? It does not matter if a person is black, white or purple…if they come from a family of bankers/musicians/coal miners then they are more likely to end up working as bankers/musicians/coal miners. You can try to regulate opportunity, but you cannot manufacture success unless you can find a way to change culture. Good luck with trying to get people to agree to that.