If you think sea level is going to rise 15 feet in a day, think again. Plus, that area is below sea level right now.
My point is that officials had been aware of the threat to New Orleans for years prior to the inundation, and rather than take the needed preventive measures, they applied inexpensive 'band-aid' solutions hoping that these would suffice.
I don't believe that government will act substantially differently as other coastal city's become increasingly vulnerable.
As problems unfold, the forces that insist that this is nothing to worry about will, through organizations such as the Heartland Institute, continue a well financed disinformation campaign that will be powerful enough to halt any efforts at preventative measures sufficient to save any of the low lying cities in America.
Last year saw a mass evacuation of portions of New York City - Is this year seeing a massive build project to increase the sea walls so that they will be capable of withstanding a storm surge at least as big as last years was feared to be? Are subway lines being elevated to prevent last year's feared flooding?
Last year New York was lucky - I lived in Las Vegas for decades, and can tell you that suckers relying on luck are what keeps the lights burning.