" I tend to disagree that people with that level of support, aptitude, and drive are the exception rather than the norm."
But is this a data based belief or a ideologically based belief? Without taking a Calvinist ("they are not favored by God") or Social Darwinist ("some races are not sufficiently evolved to a capitalistic society") position, how would you explain the entrenched poverty of the Hispanic and Black communities? Social mobility, household net worth and educational attainment data tends to argue against your position that the opportunity to succeed is more equally distributed.
You make a valid point...it is definitely tougher for people in entrenched poverty to make their way out regardless of race or ethnicity (see Appalachia). But opportunities do exist... and we should not ignore that fact. There are stories everyday of people breaking the cycle of poverty because them made choices that pointed them in that direction. That opportunity is what America is based on. If it wasn't, why would so many immigrants want to come here?