911 hijackers spend around half million undetected

I wondered if anyone here thinks that its quite amazing what all obstacles the hijackers were able to overcome without detection from a single law enforcement organization.
If you go by the Commissions information then one would have to believe that according to the commission the whole 911 operation cost between 400 to 500 thousand dollars...and that this money was wired and shuffled around in large amounts, in and out of the country , in and out of multiple (known terrorists in some cases) U.S. and Saudi bank accounts. All of the cash being spent between Dec.99 (The first date of enrollment for flight training for Atta and Jarrah) and Sept.01