If the Japanese hit the Dutch and British only, the US fortifies the hell out of Guam, the PI, Wake, etc. And the kicker is the Japanese still wouldn’t have the logistics to get much if any closer to India and Australia. Darwin would still be the world’s largest self sustaining POW camp, and Ceylon might as well be the far side of the Moon.
The US Navy already started it’s massive buildup and the prospect of fighting the IJN alone will be enough impetus to continue the build up. Not being at war with Germany means the Army will get less resources, but those resources will certainly be passed on to the British and Australians.
Japan will still end up at war with the US, just a US with a larger fleet and massively more heavily defended possessions in the Western Pacific, to the point where the USN may actually have the time and fleet train to relieve the PI (I understand that wasn’t WP Orange-5, but things change according to capabilities).
Just my take, happy for a true expert to tell me I’m wrong