There was an enormous impact of 9/11 on the US economy.
And that was one of the primary goals of the attack. Listen to bin Laden discuss the attack, and he talks probably more than anything about the costs it puts on us.
He's almost giddy, as a financially knowledgeable person, counting off the cost.
Rachel Maddow did a good segment on this, replaying bin Laden, reminding how much causing us to harm our economy was part of the plan.
I think the 9/11 attacks were largely about getting us to attack a Muslim nation in response, both to turn the Muslim world against us and to cost us a fortune.
The costs not only brought the economy to a standstill immediately after the attacks, ended all air travel right after them, the economic stoppage had big chain effects.
The government had to provide big bailouts to industries to keep them going; this was a direct cause of the Fed putting interest rates at historic lows - but it kept them there.
A good case can be made that an unintended side effect of 9/11, with the near zero interest rates, was fueling the housing bubble that created the opportunity for the Wall Street schemes and overinvestment in real estate derivates that caused the worst economic crash since the great depression.
This in addition to the long-term inflation of homeland (a term new for the US from 9/11) security and military spending increases and the wars.
The cost of Iraq, which wasn't really possible without 9/11, has been estimated at $3 trillion by Nobel Prize winning economist Joseph Stiglitz.
My opinion on 9/11 was 'do not overreact to this, don't change America, treat it as a police problem and let the military go after the perpetrators specifically'.
Instead, we re-elected a terrible president who did a lot to hurt our economy and our culture.
No one likes to admit 'the bad guy caused a big harm'; we'd like to say bin Laden caused less economic harm than he wanted. But I don't think that's correct.
In large part, as it usually is, we caused probably most of the harm ourselves. The #1 strategy of terrorists IMO is trying to trigger an over-response.
How do you even put a price on things like 'the US losing decades of global goodwill built up with the aggressive and illegal invasion of Iraq', the impact around the world?
The impact on the Muslim world being more wary of the US? Of problems yet to possibly come from things like our permanent presence in Iraq as a base?