Why Britain and America gain most from the delay

A fixed 1939 order of battle cannot represent full modernisation. New information in each year changes the next year's construction, while more peacetime permits larger reserves, trained personnel, industrial expansion, and technical iteration. Revenge-class ships have limited room for modernisation and hulls that cannot readily be made fast enough for frontline service. They remain useful for convoy protection and other secondary duties because an enemy must still detach sufficiently powerful capital ships to defeat them. Britain and the United States begin with especially large fleets, reserves, industrial systems, and room for expansion, so postponement makes the eventual balance harder for their prospective opponents. The same delay may even bring jet aircraft into service before war, adding another possible change to the forces available when fighting begins.