Who’s benefitting from war in Iraq?

What percentage of the reason we have been in Iraq so long is that Congress is funding, enriching rather graciously their constituents' contractors to the tune of billions for shoddy substandard, underperformed, incomplete work and with little oversight of money? Money that seemly faired no better in distribution accountability then Katrina's relief funding disaster, at many times the Katrina dollar amount.

Could someone either confirm or dispel the impression of terrible waste of tax dollars into the pockets as the primary reason in the delayed withdraw of Iraq at the expense brave and honorable men and women?