US occupancy of the ME initiates a feedback loop where our military presence creates cause for (often violent) anti-American sentiment. Wouldn't you be at least tempted to avenge the death of your father (or the rest of your immediate family) if they died a brutal death at the hands of a foreign superpower? The reactionary response is to bed down those anti-US sentiments with more military action, only fueling their (often rightful) discontent. This creates a paradox where the more we attack the symptoms of the problem, the worse the problem becomes.
The only way to stop a feedback loop is to break one of the steps in the loop. The end of military occupation might have short- and medium-term negative effects, but if the goal is to make US-ME war a historical occurrence instead of an ongoing (present) one, you have to stop at some point. Time ~heals~ lessens ~all~ most wounds and we have to accept that a fresh, repeatedly-injured wound is going to sting for awhile.
There's no good (or even sub-par) reason(s) to remain in the ME any more. Total US fossil fuel consumption is continuing to fall. US fossil fuel production has risen. We already nabbed the (ostensible) main culprit of 9/11 and have toppled the regimes of some bad authoritarians. None of these were noble (or even profitable) reasons to invade the ME in the first place. The wars still stand on the same shaky foundations on which they began and it's time to focus our resources into far better endeavors.
Imagine if we had instead spent all that war money on clean energy and grid storage. Even in 2003 prices, we'd be far ahead of where we are now from a total resources and national wealth perspective. Sure, building an expensive missile is ~technically~ GDP, but what good is a product's GDP contribution if we literally explode it and it does nothing for our collective quality of life?