Perhaps it would make more sense to describe it as an intentionally mistaken understanding.
We’ve been a fragile, fractured country since that day. Al Qaida - and Saudi Arabia - did us lasting, potentially terminal, damage.
In 2001 before 9/11, George W. Bush was clearly going to be a one-term failure of a president, a mistake of the electoral college brought about by complacency, never to be repeated. He would get the boot, be replaced by a better and more competent president in 2005, and that would be that. No Patriot Act. No Department of Homeland Security. No TSA security theater. No war against Iraq, no formation of ISIS, and likely no Tea Party, let alone the travesty that was four years of Donald Trump.
Saudi Arabia may have actually dealt the killing blow to this country, causing the ongoing, slow-motion disaster in politics we see today.