Okay but American blacks have NEVER felt like part of mainstream society and they are definitely the least prosperous group. That's a great big gaping hole in the theory that needs to be explained.
There is no gaping hole in the theory here, you've just failed to understand it.
Having a culture that glorifies violence and street crime and actively persecutes those who want education really, really doesn't help. That's what gangsta culture does.
I completely agree with you, and so does the article. Gangsta culture is all about glorifying poor impulse control. Note that impulse control is one of the things the article says is essential to success (and not just this article, there are tons of studies backing up that assertion). Additionally, that glorification of negative achievement promotes the opposite of the second item on the list of essentials, "insecurity, a feeling that you or what you've done is not good enough."
No group could thrive with that. So the real question is why the nearly suicidal anti-achievement attitude? Where does it come from? Why can't people understand that embracing it means forever denying yourself your true protential? The successful black people who own businesses, enter the professions, and work in academia all have one thing in common: they rejected thug culture and growing up, they were often targeted and harasses and assaulted because of it. Not by whites, but by fellow American blacks.
Again, you are correct, and the article agrees with you:
"The first is a superiority complex — a deep-seated belief in their exceptionality."
This is really the big issue facing the African American community, IMO. This one is about having a sense of racial/ethnic/cultural superiority, and they've been told they're inferior so often and for so long that they've come to believe it. People fight hard to defend their beliefs, even when those beliefs are harmful to themselves. The evidence of their inferiority (their inability to overcome the oppression of The Man) is all around them, so it's easy to excuse a lack of personal success. And if they're prevented from achieving success within mainstream culture they must seek it elsewhere, meaning the underground economy and the thug culture that comes with it. Anyone similar to them who is able to achieve mainstream success is a threat to that narrative, and stands as a silent accusation that their of mainstream success might be due to personal failure rather than the inevitable result of powerful forces working against them.
To sum up, in the language of the article:
The typical Successful Immigrant has a sense of ethnic superiority, personal inferiority, and strong impulse control, and this is why they are successful.
The typical Gangsta Thug has a sense of ethnic inferiority, personal superiority, and poor impulse control, and this is why they are not successful.
Where is the hole in the theory?