Considering the investment concentrated in such facilities and the stringent requirements of clean rooms, the 911 attacks would gave done much worse economic damage by targeting those facilities.

Are you including all the damage of the TSA and the wars that resulted from 911?

You still would have had the TSA and the wars, plus an ongoing economic impact on the cost of chip production. I'm not saying that there wasn't a lot of economic impact. I'm saying there could have been more.