Brother, this is NOT what you think - After 1991 i.e. the collapse of Soviet Union, the US Pentagonists needed an "enemy", ofcourse the billions and billions dollars worth of arms sales would have stopped and sophisticated technology would have to be abondoned as well as hi-tech professionals would have gone home and applying for job in McDonalds, Windys, Popeye's chicken, Seven Eleven Stores, Burger Kings, Wal-Marts etc.
The drying up of lucrative offers for US weaponry from around the world especially from Saudi Arabia and other third world countries would have killed the US economy then and there - This fact is pretty visible from the fact that NATO was organized to counter Warsaw Pact countries, but when their biggest and strongest enemy along with its satellite countries collapsed, why NATO was still intact and working, again "they needed an enemy".
For your kind info the 1991 Gulf War was already designed, planned and shelved in Pentagon since 1978-79 which was known as TRADOC, ready to pull out at the right moment. Was Saddam not CIA??? Is Hosni Mubarak of Egypt, Musharraf of Pakistan, The Al-Sauds not CIA???
So, bro If I were Osama and I have attacked US, why would I confess on a video tape and leave it conveniently in a cave to be picked up by the Americans??? And if I "master-minded" the WTC why the 2200 Jews working in the WTC never showed up on work on "that" particular day???
Muslims would not dare to kill women and unarmed men. This was a combined job of CIA and Mossad.