The difference is that during the reconstruction of Western Europe and Japan, they were purchasing American goods for the reconstruction and development of their economic stability thereafter. Therefore, much of that money returned to the U.S.. The boost in the American economy extended well beyond the years of the Marshall plan which ended in 1952. The U.S. post-WWII boom was fired by European demand for goods. That has not been nor will it be the case in the ME, nor will they cut us any deals on oil as a gesture of gratitude. The Iraqi people have been notably ungrateful and the Iraqi government lacks the institutions to build the infrastructure needed for their participation in trade levels that would benefit anybody, including Iraqis!! You can lead a camel to the oasis, but making the beast drink requires an undefined, unobtainable skill set. Arabs are willfully backward and fully intend to stay that way. The best way to handle them is to stay out of their way when they have a hankering to kill each other while killing as many as we can with plausible deniability.
Buying some of our goods does not constitute payment* (or gratitude), especially if we had to extend huge loans on easy payment terms (the Marshall Plan) for them to do it, and we were the sole source for the machine tools they had to buy in order to rebuild (or not buy and become agrarian societies). Europeans imposed stiff tariffs on US goods during the reconstruction period, and we went along with it. Even today, there are all kinds of non-tariff barriers on American imports, which is why US manufacturers had to set up factories in Europe to sell to Europeans. The upshot can be seen in the EU-US trade balance - we've run a trade deficit averaging $80B with the EU for the past decade.
* If doing business with a creditor is considered repayment, maybe I should suggest to my local bartender that my continued patronage constitutes payment for my yard-long bar tab.