Your article title is wrong. The strategy was always about defeating Hitler. The Grand Alliance was formed in early 1942 with one objective: defeating Hitler.
https://en.wikipedia.org/wiki/Grand_Alliance_(World_War_II)
You also make false assumptions about American readiness for the conflict. The main reason the American's invaded Africa was to gain combat experience. The Americans were woefully unprepared, and they got their asses kicked by the remnants of the German Africa Corp, but the combined allied forces ultimately prevailed.
https://en.wikipedia.org/wiki/Operation_Torch
In 1942, America was not prepared for an invasion of Europe. We simply didn't have the men and materials necessary to pull it off. Later that year the allies attempted an invasion of Europe at Dieppe. The Germans kicked their asses there too.
https://en.wikipedia.org/wiki/Dieppe_Raid
The Americans learned from both losing encounters in 1942. Primarily, they learned that they needed way, way more men and materials than they had if they were going to successfully fight the Germans and invade Europe. They spent the next two years accumulating the necessary resources and making plans for D-Day. Your contention that an invasion of Europe in 1943 was doable was not an opinion shared by the Allied commanders.
1943 saw a major bombing campaign to weaken German manufacturing. That aspect of the raids wasn't very effective, but it did serve a greater strategic purpose. The Germans had to move aircraft they needed on the Russian front to defend Germany from bombardment. In the initial invasion of 1941, Germans had air supremacy in Russia. By 1942, they had air superiority, but lost supremacy. By 1943, with the repositioning of aircraft to defend against bombing, the Germans lost air superiority to the Russians. Without the necessary air cover, German offensive operations were hamstrung, and their offensive of 1943 failed miserably, and they lost the initiative. From that point on, the Russians had air superiority and offensive initiative. The Germans effectively lost even though it took two more years to wind down. Air superiority was essential to offensive operations, and the Germans lost it in 1943.
You mentioned that Hitler stalled his invasion of Moscow for two months in 1941, and you said it was because he was stupid. The real reason Hitler didn't invade Moscow in late 1941 is because he didn't have the forces or the stable supply lines to win the battle. The German army moved so far so fast that they needed to consolidate and clean up the strongholds they bypassed on the way to Moscow to secure their supply lines. If they hadn't done this, and if we had a battle of Moscow in 1941, it probably would have turned out like Stalingrad did the following year.
The instance where your "cruel calculus" was a real issue is the final invasion of Berlin. The Americans and the western allies stopped at the Elbe River, partly because the Grand Alliance had agreed to partition Germany after the war, but mostly because the western allies didn't want to lose 400,000 men, which was the estimated military losses associated with attacking Berlin. We let the Russians absorb those losses.
Your final contention is that we invaded in 1944 to prevent the Russians from controlling France and the rest of Western Europe. That is true. It was one of the reasons we invaded, but contrary to your contention, it wasn't the primary reason. The primary reason was to defeat Hitler, the secondary reason was to prevent Stalin from controlling Europe. Both reasons were important.
