I'm not saying that everyone can succeed, not at all. What I'm arguing is that anyone can succeed, and the success one enjoys or does not enjoy depends on the choices that the individual makes. The only way that everyone would succeed is if everyone made the choice to succeed, and that will never happen.
If you buy the idea that racial bias, poverty, lack of parenting, or whatever it may be precludes success regardless of what the individual may or may not do, then you're fostering a culture of poverty in which there is no escape because the individual sees no escape.
The "why try, the deck is stacked against me" philosophy will inevitably lead to failure every time. It is a self fulfilling prophecy.