Nobody could have anticipated...
From today's perspective history is that things were rollin' along and then the economy fell apart one day.
And 9/11 was some out of the blue wake-up call.
Go back to the 1990s and there were tons of movies and books about Islamic radicals pulling off large-scale attacks on American targets. It was on most people's short-list of dreadful things likely to happen. You turned on the news an al queada or someone had blown up our embasies, tried to sink our ships... something. It was just part of ongoing life.
And the 2000s were a non-stop coruption-in-accounting circus where nobody trusted anything. (Which is part of the reason they piled into real estate, which was the old-fashioned reliable, sane investment.)
A DATA POINT: Remember when MCI-Worldcom was the corporate sponsor of the Fourth of July fireworks on the national mall? The company, one of the NASDAQ big five, signed up to sponsor the 4th of July then disappeared, rendering all their stock worthless.
Shortly before the 4th folks realized that all the Worldcom (which no longer existed) signs were not the best advertisment for the next American Century and they scrambled to write Worldcom out of the event.
That was the Fourth of July, George W. Bush style. Scrambling to paper over the sudden disappearance of one of the formerly largest corporations in the nation.
Everybody knew... just like everybody new there would be a 9/11 someday.
Never let them re-write the history you lived through.