"Okay one reason they will rebuild is simply, oil and gas."
The urban ghettos which make up most of the town don't serve to extract one extra barrel of oil. The oil and gas workers will have other places nearby to live, such as across the river in Algiers and to the west in Gretna.
I doubt real seriously that those areas will be rebuilt for the ghettos. I am not that naive. If it is rebuilt, it will be the absolutely last thing built. You know take so long that they are hopefully in a different socioeconomic class.
As far as Algiers, and the non flooded areas, people already live in those areas. Are we going to displace them so that the workers can live there? Are you familiar with the area? The greater NO area has about a million people living there that is not including the population of New Orleans Proper. They aren't all ghettos either. The majority of the people in NO did work despite what the media has portrayed. Do you really think that a major US city could survive with only inner city ghettos?