Why are the Royal Navy and Imperial Japanese Navy sometimes described as winners, and the US Navy as a loser, if war does not begin in 1939?
Short answerThat simple ranking does not hold: the US Navy's expanding infrastructure makes it a major beneficiary too, while Japan gains little if it still chooses war in 1941.
NotesThe US Navy had already undertaken major infrastructure development by 1941. More preparation time therefore benefits the United States as well as Britain and Japan, even if the relative comparison changes because the other navies also improve. Japan cannot be called an automatic winner if its political decisions still produce the same 1941 war against stronger opponents.