1. Lack of understanding of group economics.
We have a lot of black people becoming entrepreneurs but they are all individuals. Not many are linking up together. As an offshoot of that, not many are diversifying into different industries and creating linked institutions instead of fragmented stand-alones. Just today, I read a post about black people buying Euro made cars. Why don't we make our own cars, made by our own engineers and mechanics, marketed through our own car shows and advertized on our own media etc. It's not singular.
2. Poor education.
This definitely matters because often, we are smart but ignorant at the same time. We don't often seek out the kind of knowledge that will enable us to flourish. Not just in terms of financial literacy, political sciences and the like, but educating ourselves on the concept of power, why it matters, how to wield it etc.
3. Acceptance of our own.
This is a controversial one, but I think a lot of us marginalize those among us who could contribute and be beneficial to us because of things we deem to be bad. Obviously some are lost, but if we can learn to understand our peers who may be any one of the things that are regularly condemned (raised by single parents/gay etc) we might be even more prosperous as a people. Things as they are, we're too fragmented.
EDIT: poster above me actually hit the nail on the head with his second part. I didn't even think of it which is bad but the main cause of all three of the above is simple. White Supremacy.