so before i shut down this throw away account i'd like to ask this let me off by first stating i'm a current serving member in the Royal Australian Army and during our basic training we are taught everything about our military history from Colonial times to modern times ad nauseum
right so that being said the following is what i have been taught
it surprises me how little people outside Australia actually know about what Australia actually did during WW2 and probably the biggest one was almost single handedly driving the Germans out of Africa i mean Rommel said something along the lines of
"i fear nothing more than an Australian and his rifle but i take great comfort in knowing the English do not know how to utilize them properly" and also
"The Australians training is far Superior to our own"
i also believe the Japanese feared us more than any other allied nation as well some even thinking we were supernatural demons
in my personal experience very few over seas of heard of the rats of tobruk or the siege of tobruk
second is this idea that Australia was "saved" by America any one correct me if i'm wrong (with sources) but what we were taught is America was actually selfish
we asked them a number of times to help but they refused to in any way be it man power weapons or financial help and it was only after we had held off the Japanese long enough that an invasion was no longer logistically possible and Japan was on the Defensive that America decided to send "aid" but there's still this attitude that America saved Australia some how where exactly does this come from?
another quote from Patton i can't find where this quote is from i only heard it mentioned once but when he was asked by a reporter "how long until the war in the Pacific is won?" Patton reportedly responded with "give me a Company of Australian's and i'll have it over in two weeks"
so clearly at the time we had a large amount of respect but these days not very much and this ranges from people who should know this stuff
i remember there was a very recent video game developed that caused controversy because they replaced the ANZACs with American's and when the developers were questioned on why they did that they responded with "Australia was not important enough during WW2 they did nothing notable"
any way i'm not trying to start anything its just we are taught something way different to what the Americans are taught
Without denigrating the Australian contribution, I would argue that their primary effect was operational and tactical, not so much at the strategic level. Events such as Kokoda Trail and Tobruk were great feats of arms, but I don't know if I could say they were war-turning. Australia's ability to affect more than its local area was severely limited. It is not as if the RAN was capable of stemming the Japanese navy, heck, the Royal Navy got embarrassed and they were better equipped.
Even the equipment which Australia produced was heavily reliant on foreign sources, particularly motors, such as Pratt and Whitney Wasps for the aircraft, and Ford V8s for the carriers. The tanks were British and American production. Australia was not an industrial powerhouse at the time, and although Australia stretched her manpower thin, the total force numbers were still overwhelmed by those coming in from other nations.
The effects of the US Navy on Japanese aspirations to Australia, such as they were ever a significant threat, has been addressed by other responders. Australia pulled her troops back from North Africa because she needed everything to ensure her own defense. When holding the line, there isn't much left for offensive action.
In short, Australia did herself proud, but even the finest forces can have only a limited effect on a war the size of WW2.
Given the reputation and actions of Australians in the war it is regrettable that their contributions are often overlooked, but from anyone other than an Australian's perspective their contribution to the war was small enough to get caught up in the narrative of the Commonwealth in general. Both the US and the UK suffered more than 10 times the casualties of Australia, so from a sense of scale it's reasonable to see how outside a detailed study of the war Australian efforts can be overlooked. The minor Axis powers get the same treatment.
There is an argument to be made for the US saving Australia from further Japanese aggression which largely centers on the US Navy foiling the Japanese in the Coral Sea, eviscerating the IJN carrier force at Midway, and the subsequent campaign in the Solomons. After the noted battles it was wasn't materially feasible for the Japanese to launch an invasion of Australia, which could be viewed as saving.
As massive as American industrial capacity was at the time, they were using every bit that they could for the war effort, providing huge amounts of war matériel to the Soviets (someone made an excellent post on the sheer scale of the Lend-Lease Program, I'll link it when I get home) as well as financing an enormous army and navy. You guys got left in the lurch because the Allies pursued a Europe first strategy.
It's worth noting that the information you are receiving is from an entity that directly benefits from the narrative they're pushing. Be critical of your sources.
tl;dr Got lost in the shuffle
I don't know that it is often portrayed as "Saving" Australia, at least not in anything but the most reductive places.
But certainly providing aid and cover to a vital ally and in a time when their traditional benefactor was on the down and out.
Especially in consideration of the vital link of the Australia, Fiji, Panama/California shipping route was as part of Allied global logistics networks. While the RN was all but pushed to beyond India, the RAN and RNZN had little ability to deny the IJN control of the seas on their own, certainly all the fighting to defend Port Moresby by land would have been for naught if Operation MO had been opposed only by a small cruiser squadron. Thus the commitment of 2 carrier task forces, and a 3rd in the plans in the Spring of 1942, out of just 5 on hand must be seen as a major shift of a limited resource to cover an ally without equivalent capability. All in defense of maintaining an open link to keep resources and shipping flowing.
So it is probably beyond unfair to claim America "saved" Australia from subjugation, but the argument of preventing a severance of supplies from the rest of the allies in both military and civilian goods is less easy to dismiss.
It should be noted too that contemporary reports don't denigrate the ability of the RAN or RNZN, and their presence was certainly welcome at Coral Sea and later in the Solomons. But it was also understood that the USN could provide everything their welcome allies brought in a pinch but the same could not be said by their Commonwealth peers.