David M Glantz discusses in this lecture that the tide had really turned against the Germans as early as the Battle of Moscow. And indeed, following Germany's string of defeats in 1943, their army lost much of its original strength and flexibility. By 1944, the Wehrmacht had be soundly beaten. The only question that remained was how much blood still had to be spilled to end the war. I would argue that, had AGC not been so soundly beaten, Germany would still possess its fundamental disadvantages while the Soviet Union had its fundamental advantages. Such a hypothetical situation would, in the end, have only cost more lives and more time.

The only difference would be operational, not strategic. Considering previous Soviet victories in Crimea and Korsun, as well as the larger in scale victories over Army Group North Ukraine one month later in the Lvov-Sandomierz offensive and over Army Group South Ukraine two months later in Iassi-Kishinev, it is clear that by June, 1944, the Red Army had gained enough qualitative material advantages to outfight the Wehrmacht throughout the entire Ostfront barring a major leadership failure. Remember also that AGC primarily consisted of infantry divisions. It is hard to imagine such units winning the war for Germany at this late stage in the war.

Bagration was an essential key to the later scope of the war in Poland and Berlin, but it was not essential to eventual Soviet victory. Considering the Red Army's quantitative tank, artillery, and aircraft superiority over Army Group Center prior to Operation Bagration, a fighting withdrawal would've been the only likely alternative to AGC's encirclement. It simply is hard to imagine the Red Army being fully routed at this stage when Luftwaffe support was minimal and armored strength near nil. While a defensive success may have bled the Red Army, such a campaign would not significantly slow down the Soviet advance, nor would it much trouble STAVKA, which by 1944 gained access to the huge manpower levies of the classes of 1927 and 1928.