One key to WW2 victory in Europe and the Pacific was logistics support. Liberty and Victory Ships got massive quantities of stuff where it was needed and were built very quickly. They weren't spectacular for the highest performance and quality, but were notable for getting the job done when needed.
By way of contrast, Japan's shipyards were barely able to keep up with repairs, conversions (e.g. from merchant ships to carriers), and warship replacements. They were not able to keep pace with USN submarines' predations, and IJA and IJN soldiers, airmen, and sailors suffered for it.