You do have a point here, TOS. One has to keep in mind that Britain had almost exhausted its resources on manpower by the fall of 1944. The UK could no longer make good the losses on the continent. A stronger Luftwaffe would inflict more casualties and losses on the Allied. One can perhaps imagine a worst case scenario on the western front where the Allied offensive grind to a halt along a line streching from Antwerp-Brussels-Bastogne to Strasbourg. On the Eastern Front the Russians, less sensitive to human losses and with shorter supply lines and not depending on sea transport, would continue to push the Germans to the west. Agreement or not, I do think Stalin would have taken the opportunity to push all the way to the North Sea if there was an American-British stalemate on the Western Front. The political landscape in postwar Europe would have been quite different, with all the territory of Germany, the Netherlands, Denmark and perhaps Norway under Soviet control.