Simplistic, simplistic, simplistic.
Anyone who knows anything about the ETO of World War II knows that the Russians did the heavy lifting. However, it would have taken the Soviets a great deal longer, that is assuming they had not been completely defeated by Germany, if the British Empire and Dominions and the U.S.A. had not been in the war. Further, as ugly as it may be to say this, by 1944 the U.K. and Canada* were at the edge of their manpower and endurance, without the U.S. they would not have been able to sustain the effort, this was not true of the U.S.A., although it would have indeed have been vastly more difficult.
To quote John Donne: "No man is an island, Entire of itself, Every man is a piece of the continent, A part of the main." That also applies to the World War II Allied Powers.
*Australia and New Zealand after the Desert War had their hands full in the Pacific.