The ghetto culture is a very strong absorbing point. Once you are there, it is very difficult to get out, and your children will also have a very hard time. The problem with the ghetto culture is that is harbors values that a very different from mainstream culture, in particular regarding work habits. Those values are instilled by your environment (family, neighbors, community) and when you grow up around peers with poor work habits, it is difficult to acquire better habits.
Maria Sáez-Martí and Yves Zenou make this point and add that even when parents are forward-looking and care about their offspring, they will not make the investment to teach their children good habits if employers take the cultural environment of a potential employee as a signal of work habits. They discriminate, and because they discriminate they turn out to be correct. That is a vicious circle that is difficult to beat, but initiatives like affirmative action can overcome this. The condition is that quotas be high enough.
Affirmative action can be implemented in two ways, imposing quotas on good jobs, and imposing quotas in the majority group (putting some of the ghetto in the mainstream group of applicants). Low quotas are also improving work habits in the ghetto in the second case, but are detrimental in the first case. This is because the advantage of better work habits is absent, wages of good workers are lower and parents put less effort in educating their kids. With the second case, wages of good workers remain high, and parents will help their kids who have then a chance to prove themselves. An alternative policy, integration is only beneficial to the ghetto, and obviously the others will resist integration because it hurts their work habit.