Deployment cycles certainly had an effect on the war's winnability. Wesley Morgan's book The Hardest Place directly addresses the difficulties faced in the Pech Valley due to our rotations. We consider theater-level changeover to be a bigger issue. A new ISAF commander would show up and they would have a new plan, which means it's time to scrap the old one. Any progress made over the previous year would be halted to pivot to the new priorities. And an even bigger contributing factor, probably the biggest, to the war being lost was the inability to build a stable government. That responsibility fell on the State Department.