I personally think it's a problem of self-interest and lack of care for the community. Most people have little to no exposure to the type of poverty that develops in urban centers, so why would they have any interest in it? It's a population that is easily marginalized and relatively "hidden" such that the average American - the white, middle class, suburban-dwelling family - has no exposure to the problem and, consequently, has no reason to care about it. As a society, I think we need to become more focused on the status of the average person and ensuring that those people have what is necessary to be independent, self-sustaining people.
The problem of America's ghettos is a complicated one, indeed. I think it's a fool's errand to try, as so many people do, to find a root cause of why inner cities have degraded so sharply in the last half century. However, I think fixing them is easier than almost anyone seems to think. To me, the easiest and most logical, and probably most impactful, thing that we could do to address inner city poverty and decay is to have a new New Deal that is city-centric. The New Deal focused largely on rural areas, because they were the most impoverished at that time. Now, infrastructure is shit, trash is strewn in the streets, and people are jobless in the ghetto. Why not pay anyone who wants a job a wage to clean the place? Mow lawns, pick up garbage, deconstruct abandoned houses, landscape lots, etc. At $10/hr, I think there would be no trouble attracting people in all the country's ghettos to sign up. There's no dignity in the ghetto; that's been my observation from living in one for most of a decade. Employing people while sprucing the place up would be a great way to bring some back.
I agree that the solution is seemingly simple - or at least as not as complicated as it is often portrayed. Unfortunately, we don't have the political will to make it happen.