There are subcultures in black America that are just as successful as some subcultures in white America are unsuccessful. Culture is a powerful thing and is not easy to change. The roots of what we think of as black culture were addressed by Thomas Sowell in his 2005 book "Black Rednecks & White Liberals". I haven't gotten around to reading it, but it's an interesting thesis.
http://www.amazon.com/Black-Rednecks-Lib...0910&sr=8-5
As a comedian once pointed out, why is it that some people who have been here for generations can't find a job no matter what, but some poor Mexican guy can find one 15 minutes after his feet are dry? It may be somewhat racist, but it is thought provoking.