One of the major reasons the US concentrated its forces in Europe first was the existence of two long range bombers (B24 and B17) that could easily be flown to an unsinkable aircraft carrier ( England) and from there to the other unsinkable aircraft carrier ( Russia). We could bomb Germany and Italy from bases in England and then North Africa. The geography favored our helping Russia since invasion of Germany over the Northern European Plain was a great fear of theirs ( as it was and is of Russia). The geography afforded the opportunity to get the Germans between three potential fronts, Russia, Northern France and Southern France. The Pacific offered no such luxury.
In the Pacific the war had to be handled by carriers given the distances between potential basing areas. The island nature of Japan’s empire in the Pacific made carrier based aviation and amphibious operations the most effective use of men and material. Until the introduction of the B29 we did not carry the war to the home islands, we used platform bombing but it was most in the SW Ocean Area. We propped up China to fix the Japanese forces in China so they could not reinforce the island garrisons. The bases in China for the B29 were not as favorable as the islands due to weather patterns and unreliable local security.
MacArthur was the second front in the Pacific since the Chinese were incapable of doing more and the Russians were grinding down German forces especially after Germany invaded Russia.
The discussion of who controlled what will go on for ever but when you look at it from a pure logistics standpoint there was really only one way to fight the war. I agree that Germany’s last intention was to invade the US it would have been a nightmare for them to supply their armies.