Most of NOLA was not "depending on the Gov" There are a ton of 'working poor' people who work at least as hard as you do, with a lot less to show for it, and often receive nothing from the gov. And what little they had was destroyed, with no money to 'get out of town' to go.... where? Packing up and leaving the state for a few days, with a cost in the thousands of dollars is simply not an option. Try walking in someone else's shoes.
You want to blame someone, blame American Business Culture. Make money for the top dogs and stock holders while the Gov picks up part of the employees' tab to get by, to protect those profits rather than pay living wages.
So don't assign any culpability to the government. Wow
Culpability to what? More than one idea in there.
http://www.cnn.com/2014/02/12/justice/louisiana-nagin-convicted/
When government officials are more worried about their own income than that of their constituency; there might be a problem.
Grading the response of NOLA government officials both past and present for emergency response planning and implementation:
http://www.chron.com/news/hurricanes/article/New-Orleans-strayed-from-evacuation-plan-1491205.php