Greed

People who have few motivations other than self-promotion and money tend to see events from the perspective of how it would enable them to loot somebody.

The Iraq War is not about looting Iraq, nor has it ever been. It is also not somehow a way for George Bush or Dick Cheney to get rich. This is naive and distracting from the real and important issues. These things are what's called "conspiracy theories." Conspiracy theories have only three sources, of which I'm aware:
1) Boredom - People come up with conspiracy theories because they're "fun" or "interesting."
2) Naivite - People believe in conspiracy theories because they don't know enough to realize how improbable the theory really is.
3) Lazyness - People believe in conspiracy theories because it's easier to believe some powerful force is keeping them down (or ignorant) than to face the facts that: a) everything is not perfect and b) it takes a lot of effort to (still imperfectly) understand complex things.

Ironically, a real conspiracy, supported by real evidence, would not be a conspiracy theory like what I am describing. By "real evidence" I don't simply mean, "circumstantial, confirming statements." You can come up with circumstantial, confirming statements for anything. Here's an example:

Arizona causes pneumonia.
--The rate of pneumonia is 4x higher in Arizona, even though AZ has relatively low amounts of air pollution. How can that be? There must be some SECRET thing in AZ causing pneumonia!
--WRONG - old people move to AZ, and old people get pneumonia way more often. There's nothing to the 'conspiracy.' I know you may take offense at this, but most of you people who think that Dick Cheney organized the Iraq War as part of some grand conspiracy to help his former employer sound just as ludicrous as my Arizona example does. The military-industrial complex is far smaller now than it has been, on average, since World War II. It isn't likely to grow significantly, as compared with the Nation's GDP, either.

The Iraq War has never been about greed. But when you, yourself, know no higher purposes than greed, it is hard for you to understand the complexity of what's really going on.