Clearly there are psychological issues at play that makes us care greatly about large disasters, but that still does not make it rational to compare individual events to decide what resources to use to fight a type of event as a whole over long periods of time.

I'm talking about the sum total of all auto accidents over 12 years an the sum of all terrorist attacks over 12 years.

Even 12 years of auto accidents don't add up to one major terrorism event.

How so? 420,000 people died in car accidents. 2,700 people died in the biggest terrorism event to ever hit the U.S. So that's deaths. Economic impact - no brainer, car accidents have bigger economic impact. By any measure, car accidents have a bigger impact in aggregate than terrorist attacks in aggregate.

If there was another 9/11 or a Boston bombing happened every year, the country's economy would be massively screwed.

I don't even know what to say to someone that writes this.

Attacks on the level of the Boston Bombing happen every day in various countries around the world. But something like 9/11 or OKC, that kind of stuff doesn't happen every day. One of those was by far the most incredible act of terrorism in the modern world. Heck, even car bombs that kill 100+ seem to happen every couple months.