There isn't a major city on the planet that could remain solvent when 80% or more of its tax base is destroyed and the rest damaged, it's residents have all fled or been relocated, and its businesses all shut down.
No tax revenue, no money to pay the debts, let alone the employees. Every city in America functions on debt, issues bonds to pay for large projects with long term benefits for its residents, now those public works are gone but the debt remains.
NOLA affects everyone. It's not only the biggest port complex in the USA, it's the port that serves the entire Mississippi river inland shipping system, the only port in the nation equipped to unload oil supertankers, and the area that services a large chunk of our domestic oil and gas production. The people who run these industries need a community to live in, housing, services, and so on.
NOLA has always been and always will be the most critical link in the US shipping chain, without it we can't efficiently export grain or import commodities to the heartland.
I hate the thought of having my tax dollars go to rebuilding as much as you do, but if the feds don't get involved in sorting this mess out, what already looks like a likely recession will turn into a certain depression. Everybody is to blame for this, because nobody took securing our most strategically important city seriously, and the entire government, red and blue alike, functions on the same model of debt finance.
That makes us vulnerable, and Katrina's going to hurt everybody whatever the politicians decide to do.