Lets be honest You have successful and hardworking African-americans but unfortunately those with very misaligned priorities are constantly making airwaves.
I would imagine the reason been that a good segment of the African-American community is simply missing lots of positive male role models to put their family units together. Family is what Africans have in abundance.
Some (not all) African Americans here do not value education, or the importance of good work ethic the way they should.
I feel that it is a number of factors including what you said (the lack of fathers). Also, many low-income African American do not have role models in general who can show them various paths in life. The following stories are only speaking to my personal experiences and are not generalizable to the entire African American community.
My high school
Speaking as someone who went to a low-income high school, the only students the counselors and teachers helped in regard to applying to college and applying for financial aid were the top 15 students. I say that as someone who received all the help I needed while some of my classmate sat around clueless about the entire process. There were plenty of classmate that I personally felt were smart and had potential, but they didn't receive the support they needed at home or in schools. We are talking about potential first generation college students with no one to help them. I don't care what anyone says, people need help or someone to show them the way. A 16/17 can't figure it all out along especially if they have no context. I graduate from high school in 2004 and I'm sure the way things worked haven't changed and lots of young men and women have been lost not because they are stupid and lazy as many like to assume.
My experience as a teacher in a low-income school
Based on my experience as a teacher in a low-income school, I would never send my children to one. The students at my school did not have the same resources, in school learning opportunities, or out of school learning opportunities. Because of corporate sponsored scripted programs that were placed in the school, the student rarely even learned science or any subject outside of reading and mathematics. Because of discipline issues, time issues, and various academic issues with other students, I wasn't able to help move some of my brightest students to the next level (we are talking about gifted and potentially gifted black students). We teachers in the building were many of their only educated role models. Many of their parents were young, single and high school educated (if that). The major accomplishment for many of these families for their children was to graduate from high school (that was the goal post). The discipline and fathers in the household were lacking (the ones with fathers were generally well behaved).
As a researcher, I've learned that the outcomes for most third generation black immigrants is similar to that of AAs. That has more to do with segmented assimilation than it does third gen'ers being stupid and lazy.
Honestly this is a multifaceted issue. There are structural/institutional factors that play a role AND individual factor that play a role (one of them is internal locus of control which I mentioned in an earlier post).
I've been rambling...sorry. Again, I am just tired of these conversations being field with stereotypes and condescension (that is why I posted actual research). It's not good to be smart and ignorant at the same time.