The Germans lost because they ran out of fuel and ammunition and men.
They figured to capture American supplies and fuel dumps. It was much closer than it might have been.
The American Garand was the best rifle of the war; Arguably, the 1911 A1 the best pistol of the war.
The Germans had the best machine gun, probably the best artillery.
The Russians had the best tanks. (When considering cost effectiveness). German Panzers were not that effective because of their weight.
The Americans had the best aircraft, and Navy.
>>The Germans had the best machine gun, probably the best artillery
We (the Americans) had the best artillery fire control. We had the ability to bring all fires from a division and even corp-level assets onto a spotter’s target. This was devastating.
VDH also thinks two other aspects of American artillery were game changers. First, the proximity fuse. Second, the time-on-target barrage. The last gave a much better chance of catching enemy troops out in the open, the first a better chance of getting them in their foxholes/trenches.
He talks about this in his The Second World Wars lectures he did with Hillsdale College. Worthwhile.
https://online.hillsdale.edu/landing/the-second-world-wars