If I were Boeing, I wouldn't open the line again. I would be designing the next generation of Heavy lift, waiting for the current C17 fleet to begin Txing. Then I would go to congress with my hands out, saying there is a new, better design ready to come off the drawing board, and all that is needed is a injection of taxpayer money to start production.
Next thing you know, the main operators are lining up to purchase the new model, and second/third tier users start scooping up the used models around the world for civilian use, a la AN-124 model. Concurrently, Boeing works out a deal with an arms length subsidiary to do refurbs of these used models, and provide ongoing support.