Katrina was classic America at its worst. It's a tendency to focus on the areas you can't afford to ignore while ignoring the rest. That happens a lot. Louisiana and Mississippi, for example, are hardly just neglected in terms of natural disasters and prevention.
Check out how they rank in a lot of things, according to the U.S. Census:
#1 & #2 in unemployment rate:
http://www.census.gov/compendia/statab/ranks/rank25.htm
#1 & #2 in percent of people below the poverty level:
http://www.census.gov/compendia/statab/ranks/rank34.htm
#47 & #50 in
median household income:
http://www.census.gov/compendia/statab/ranks/rank33.htm
#1 & #3 in infant mortality rates:
http://www.census.gov/compendia/statab/ranks/rank17.htm
#44 & #47 in percentage with a college degree:
http://www.census.gov/compendia/statab/ranks/rank19.htm
#1 and #9 in traffic fatality rates:
http://www.census.gov/compendia/statab/ranks/rank39.htm
and, by another survey, #44 and #48 in terms of education:
http://www.morganquitno.com/edrank.htm
Both states were disasters long before Katrina came around. I would even argue that the chronic problems above are more nefarious and deadly than anything Katrina inflicted.
But comparing this to, say, the flood prevention projects of a country like the Netherlands isn't even apples and oranges. Whereas the likes of Louisiana and Mississippi can be conveniently ignored on a federal level, if the Netherlands ignored their flood-prone lands they wouldn't have a country to begin with. Almost the entire population is at risk -- rich and poor alike.