Affirmative action as a policy is a nice theory, but the problem has always been one of culture. If someone grows up in a culture where education is actively promoted, they'll be inclined to pursue advanced education. If they grow up in a culture where education is actively looked down on, they're probably not even going to graduate high school. The importance that a culture places on education is directly proportional to the amount of education someone from that culture is going to pursue. In many places in America, cultures tend to isolate from one another based along racial lines, so we tend to see culture as a function of race, but that's not always the case; a white boy raised in the projects has a lot more in common with his predominantly black social group than he does with some white kid from Scottsdale. But you can't build an affirmative action plan around culture since that's a lot harder to define than a skin color. And that's why affirmative action as a policy, as well-intentioned as it may be, will never work.
Instead of focusing on throwing money at traditionally disenfranchised groups (primarily black people), they need to take steps to make education seem a viable path for someone who has grown up in a culture where education is frowned upon. How do you do that? I have no idea. But until you change the stigma of education within those cultures, you're not going to see people raised in them pursuing degrees at an increased rate.