80% of Germany infantry was lost fighting against Russia, Hitler lost the day they decided invade Russia. Russia lost over 20 million people against Nazi regime, US lost more people to car accidents than battle casualties in WW2. This is a fact. They only declared war on Germany after they lost momentum in Russia.
Japan lost 2/3 infantry in North Asia, they lost the day they decided to invade China. Russia already made agreement to invade Japan after Germany was defeated, Japan was doomed with or without US involvement. Both countries lost because of their hubris.
US did a great job in the Pacific theatre and hastening the end of WW2, in the long term, the outcome would've been exactly the same. Japan never had intention nor resources to occupy Australia. Their war objective for Australia was to prevent US using Australia as a military base.
