"You're 50% more likely to be killed by lightning than by a terrorist." or "You're six times more likely to be killed by a police officer than by a bumblebee."
Or the somber "You're 150 times more likely to be killed by a motor vehicle than a terrorist." (The War on Vehicles should apparently be funded to the tune of $150T a year, if I understand the value of American lives properly.)
The entire country would be in ruins. There would be no more cities, and the economy would have ground to a halt. We would all be living in a post apocalyptic nightmare, with knock on effects leading to far more deaths than the direct numbers from the attacks.
This is why I hate these comparisons to heart disease and whatnot.
My point was not prediction of specific outcomes, but rather to illustrate the tremendous disparity between the two scales - even in a year when we lost an order of magnitude more people to terrorism than is typical.
(You are also correct that there are substantial effects beyond the direct loss of life - but that is true with heart disease as well.)
"The entire country would be in ruins. There would be no more cities"
This is still exaggerating the scale.
If we say 3000 9/11 sized-attacks and 3000 dead in 9/11, that's 9 million people. In that time, our population grew by 50 million.
If we say the 9/11 attacks destroyed 10 million square feet of office space, that's 30 billion - about twice what we added between 2003 and 2012 (per http://www.eia.gov/consumption/commercial/reports/2012/build...), so plausibly about what we've added total in that time.
There may be "no more cities", but it would be due to a response of radical decentralization (probably not a bad move, in that situation) not because the cities were physically destroyed.
How many Americans had the Nazis killed when we invaded N. Africa? Surely a tiny, tiny fraction of the number who had died in coal mine accidents that year. So?