I would say that depictions of doom and gloom tend to lower market values, all the attacks and warring also attributes.
Although it is noted that people would have made a fair amount at the start of this whole problem, like they did at the Start of World war II.
As with any demographic study there is a balance, A point where a peak is reached and it fluctuates with a point below that peak, a bit like two numeric figures seesawing. The reason this occurs is due to a mixture of saturation that causes a loss and then the loss causes a gain, which brings it back to saturation again.
some would call this bouyancy.
Okay, so the economy has been hit, it drives a stake not just through the heart of the US but it stems globally, as one of the main factors for the strength of the Dollar is its Wide use outside of the US as currency.
When some companies mention a loss, they neglect to mention where the loss is derived, some such companies might have had shares in the companies that are now filing for bankruptcy which would mean that themselves as investors have lost money thus creating a knock on effect.
If theres less aircraft in a way it's good, less airborn pollutants being strene to the heights of our atmosphere. Of course "To deal with the ecology has it's toll on the economy" (I'm sure someone wishes they quoted that.)
There is the point that although WAR is negative at it's death and destruction, it also has it's possitive notes, that being of RESEARCH.
Presently I would guess that companies doing toxicology research or manufacturing cures for biological toxins are making a pretty penny, Not to mention companies creating surveillance equipment and other inventions that probably wouldn't have seen the light of day if something hadn't of occured.
Also the New laws that are passed on not just terrorism, Building legisilation is probably also feeling the full force, like better foam sprinkler systems, Kevlar jackets for building pillars not to foget better security.
Theres possibly a method of having something similar to a smoke detector, that instead of detecting the molecular disturbance of smoke through a lazer, could do the same with germs.
So no matter how depressed it seems, no matter how much recession occurs to begin with it will pick up and all the people that you feel have died in vane have in fact indirectly shaped a future which I hope is a more positive one. (This I would class a better thing to do than building some monument)