Japan attempted to defend their transports across an island empire, but they invested little in anti-sub technology. Their transports were easy target practice for our subs, even before the rest of the fleet arrived. Honshu could not import resources to feed their factories. Their ships and planes did not have enough fuel to train properly, they could not upgrade hardware without resources, and their troops on remote islands could not be supplied.
Their only chance was to ferry natural resources across the short hop from the mainland. Their entire fleet would have been needed just to protect their transports, along with CAP flown over the fleet by land based fighters.
China is not an island. They can import resources by land from their ally Russia, the stans, India, etc... Russia alone has vast resources in Siberia, which China will be happy to help them mine. China can stay in the field for years, waiting for voters to tire of a war where no American territory is as risk. They proved this model in Korea and Vietnam.
Japan enraged US voters with a sneak attack. Voters were behind FDRs declaration of war. China has been careful not to directly threaten any US territory. Just far away places that most Americans have never heard of, or care about. Will voters really send their children to defend uninhabited islands just so the Phils can fish there?
