If their goal was to destroy our society, they certainly got quite far with that. Since 9/11 we have abandoned American optimism, openness, and sense of a positive future in favor of ideologies that more closely resemble the paranoid reactionary beliefs of the terrorists.
I'm fairly sure the cold war paranoia pervaded society at least as much as, if not far more deeply, than post 9/11 effects. Also, let's not forget the internment camps for Japanese after WW2.
We changed, but I wouldn't call that change the kind of "destruction" that am Qaeda had in mind.
