Well no - the metric you have given is people/seconds/people which is people/(seconds*people) which gives 1/s which is frequency and not time.
But anyway I have found that data based decisions and policies tend to produce better outcomes than emotional based ones.
I do find my theory sound - that currently in the world there is no terrorist organization (or even state actor outside of Russia/China) that is capable to deliver enough pain to convert the US to failed state.
The Russians were hammered terribly in WWI and WWII and survived - 20-40 million lives lost. Germany was razed and survived. Poland was decimated and survived. Japan got direct nuclear hits and survived as a state. Israel is under constant real treat for a tiny country and is doing fine.
9/11 was a black swan - a lot of systems already in place failed. The subsequent plots were all incompetent and much smaller in scale (which we are thankful for).
So the statehood of the US is in no danger. And there is tiny danger for the civil populace.
There may be a lot of factors that could turn the US into the Mad Max world - economic collapse, ecologic one, meteorites, IP laws gone berserk.
But the idea that terrorist could cause the fall of the US don't hold to basic napkin math.
