I'm guessing that the CIA didn't gather this info...it came from a outside agency (like Germany's BND or the French secret service). This story left numerous holes and unexplained items.
As for the attack being called off...there is an odd circle around Al Qaeda consisting of Iran, Saudi Arabia and Pakistan...with various political and religious leaders exerting a bit of influence over Ossama and his boys. An attack like this would have left the US no choice about invading Pakistan...which second level leadership in Pakistan which is heavily in support of Ossama...may have come up to realize the implications and simply hinted to Ossama that they didn't want their gravey train in Pakistan to come to an end. Afghanistan was a relative cake-walk for the American military...Pakistan would have been a summer picnic in comparison...with almost no military willing to stand up against the US Army or a bombing campaign. I suspect this stern talk with Ossama probably took the operation down...but they still have the weapons and the technology...nothing has changed.
Our borders are completely open and the threat is just as bad today as it was on 9-11. Nothing has changed.