That's an absolutely valid point, but there are two major factors here that don't apply to "normal" disasters:
1. At some point, every single person in the city of New Orleans will be evacuated, or will die. This -- in combination with the fact that almost every building in the city has sustained some kind of serious damage -- means that New Orleans will be "starting over" in a way that no other city has ever done.
2. The geographic reality in which New Orleans exists (the changing terrain and sinking ground at the mouth of the Mississippi River) dictates that the long-term viability of the area as a major city will decline over time -- a situation that no other city has really faced.
Yes, it looks that way. I remember for years NO was warned that this might happen. And it sure has. I dont know how bad the situation is, but if this crap continues, people in the US are going to turn their backs because of these lunatics.