Well, the Military Industrial Complex has benefited. Halliburton has profited. Dick Cheney has profited ... many people have profited but has the United States as a whole profited? Not at all in my opinion.
How can one start a war with an idea? Terrorism is an idea ... it is a perfect war for the hawkish war-mongers because it can be sustained forever. Thus, they can make money from killing people continuously.
The War on Terror is a bloody shame. It defies Life and existence and it has no resolution in its plan, except for the subjugation of people.