The
Minnesota Transracial Adoption Study looked at black kids adopted by "advantaged" (middle to upper-middle class) white parents during their first year of life. The kids were raised entirely in white, middle-class culture, going to middle-class schools.
"The studies' general findings were that the IQs of children of a particular race did not differ significantly depending on whether they were raised by their biological parents or by adoptive parents of a different race."
I have no idea whether that is actually the case(and I have my doubts about "studies,") but for what I said, its irrelevant. There are varying degrees of intelligence, but except in limited circumstances it's not a factor in success or failure.
Most people have all the intelligence they need to be successful. Intelligence is not, IMO, a primary factor. It's about culture and, therefore, values...not raw intelligence, but how it's applied.