Define "most." By my definition, most U.S.servicepersons will not be home by 2013.
I foresee multiple enclaves of U.S. servicepersons, numbering in tens of thousands, in Iraq for the next several decades.
There never was an exit strategy. Why else the billion dollar embassy in the Green Zone.
We will be there by the thousands until the water of Iraq finds its own level, protecting the oil. That was always the issue.
In short,no.