New Orleans would NOT have been rebuilt by market forces. But if you pour enough federal tax money into a sinking hole, you can make miracles happen.
New Orleans was founded in 1718. The city has survived floods, fire, disease, wars and hurricanes. It's the birthplace of jazz and a unique cuisine. It truly is one of the few culturally unique places we have in this nation.
Abandon it because of one hurricane? Un-American, I say.
New Orleans gave us our one major victory in the war of 1812 vs. the British. That whole war was an embarassment of failure (the burning of Washington, failures at sea, etc.) save for the bravery of New Orleanians. Against overwhelming numbers, New Orleans turned back and humiliated the British invasion force.
So now, after a bad hurricane, we just let it rot you say. I say history matters, culture matters, places matter.
As for spreading around the cost of insurance.. well, it gets to a point where the cost is too much for the local market to bear, and it really must be spread nationally.
The entire nation uses products and services from California and Florida. A person in a safe state, oh let's say Kansas (we'll assume no tornadoes) probably a) watches Hollywood TV and movies, b) visits Disneyworld and Florida beaches and c) has Florida orange juice, sugar, and beef in their kitchen.
So even though you may not live in Florida, you benefit from Florida in many ways.