Even for reasonably-stable middle-class people, moving—especially out of a place like NOLA—is going to cause financial hardship.
In any given year, 15% of the population moves, and 40% of them move to a different county. https://www.census.gov/library/stories/2023/09/why-people-mo.... It's insane to say that most people wouldn't be able to make a once-in-a-lifetime move just a couple of towns over sometime over the next few decades.
There will need to be a federal bailout to relocate everyone who needs help. The government should also probably announce a policy that there will be no future disaster relief that involves rebuilding, only relocating.
New Orleans will be the first, but not the last American city to collapse. Miami is probably next. Salt Lake City could very well run out of water, nevermind the increasingly toxic lakebed. Phoenix too. In the next hundred years people are going to learn why environmentalists use the word "sustainability" so much.