But heck this is all speculation. There are so many unknowns. Maybe the local black leadership will do what you say, so they can get very, very rich, and can retire in style. Charity begins at home.
Public housing projects are going out of vogue even in cities that aren't flooded! A number of the 'high-rise' projects have been torn down. Other cities are attempting to distribute those on public assistance into more condo-style communities, or into distributed low income housing. I don't really see why they would rush to rebuild 'projects' in the sense of what many imagine when they hear the term.
I fully expect that low-income housing will be built. In fact, it will be a priority, but I doubt that it will resemble what was there before, and I certainly don't think it will of the high-rise sort. Slums will surely return some day, but slums are rarely intentionally built that way to begin with in the U.S. (like shanty towns are in the 3rd world). Most importantly, part of what I'm getting at is that I think supply will meet demand, and if the departed 'underclass' resettles elsewhere by and large, the demand will not emerge for quite some while again.
Anyhow, that's just how I see it. I think that the historical New Orleans black community has been irrevocably shattered and dispersed and will not return. I think a Latino community will replace it in the socioeconomic order of things. I am certainly not saying that a black community will not reform in New Orleans, just that it won't be what was there before, and it certainly won't start from the same baseline.