“...Admiral Rader advocated that Germany seize Gibraltar, the Med and North Africa, and Egypt, then extend their forces down the east coast of Africa and interdict the flows of Mid East oil and Allied supplies to Russia, and sever England’s lines of communication with India.”
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An excellent point, and the Admiral wasn’t so far off the mark. Of course, the problem was that Hitler and Army generals could never quite grasp the ‘big picture’; German military thinking was, and had been for centuries, confined to land warfare against their neighboring countries. Therefore when Raeder presented his tours d’horizon, the reaction of Hitler and the Army staff would likely have been something like, “Huh?”
Pressing the Danzig issue too hard, Hitler though provoked war earlier than planned, perhaps because he learned that he was suffering from tertiary stage syphilis. As you point out, under the stress of war, neither Hitler nor his land-minded generals fully recognized or exploited the opportunities of the larger strategic context.
In contrast, the US and Britain planned and conducted WW II on a global scale. Weapons development and production programs were geared to the demands of such an effort, the economy mobilized, and millions of troops inducted and trained.
As John Keegan has pointed out, even in the 1920s at the Army Air Corps war college in Montgomery Alabama, when most military aircraft were open cockpit biplanes, a class final assignment called for the students to project the specific targets and the kinds and numbers of aircraft needed to bomb Japan into submission. The students were to become the wartime generals who did just that in practice.