For reasons both physiological and cultural, negroes tend to be more inclined to aggression and violence. This manifests in increased rates of homicide and assault. This creates a social atmosphere that is not conducive to business, crippling the local economy and further fueling poverty- which makes theft, selling drugs, and similar activities than offer the possibility of quick cash- extremely enticing.
It's all compounded by the fact that the first thing successful negroes do is leave the negroe community. Instead of investing in their people and neighborhoods, they seek to live among affluent Whites. Capital is not invested in the local community and economy and the cycle continues.
We've seen an entire continent fail to develop- even in regions rich in natural resources (precious metals and stones, for instance) because the negroe race is not fit for advanced civilization. Indeed, the only advanced civilizations to arise in Africa in antiquity were in regions which had a heavy influence from the Mediterranean, no doubt including not only information but also genetic drift (the two components of social drift). In modern times, the only advanced societies to arise in Africa have been largely Arab/Middle Eastern or products of White colonials and social architects.
The reality, as demonstrated in the American inner cities and the continent of Africa is that the negroe race, taken as a whole, is simply unable to build or function within any advanced society. And deep down, they know it. That's why there remains, at the heart of Black culture a certain uneasiness and a certain envy of the other races. It is why there is an unspoken acknowledgment among the Negroid people that their best and only hope is to breed up- hence the calls for mongrelization and intermarriage as the Negroid race turns to the more evolved races as their only hope of salvation.