I've ridden both the "Loneliest Highway" in Nevada as well as the perimeter of Australia. Australia has a lot more empty spaces in the north and west. For example, most every place I saw in Nevada was still on the power grid whereas in further reaches of Australia the road houses generally had their own diesel generators. Another good comparison was that Australia as a whole was similar in size to the lower 48 US states with 10% of the population. I met a guy with 4 camels who had walked from western-most to eastern-most Australia. We figured that until he got close to eastern Queensland, he had crossed 4 sealed roads [equivalent of walking from Oregon to Pennsylvania and crossing only 4 sealed roads...]. Parts I rode on were sometimes remote, but not necessarily more "rugged" than parts of NV I've ridden.

Now with that said, there are broad stretches of nothing and if one were on the outback tracks, it could be a while to see someone. On other hand, since there were few sealed roads, there was also a moderate amount of traffic even in outback on those remotest roads. Also, there was a set of outback stations and roadhouses. The largest gap between roadhouses was 286km between Roebuck Roadhouse (near Broome) and Sandfire Roadhouse in the Great Sandy Desert. A more typical gap between either a roadhouse or a small settlement might be 100km. So, while I was cycling in the outback, I'd carry some food but typically not more than a day or two.

A much larger proportion of the population lives either: in rough stretch between Adelaide and Cairns or in Southern WA or in Tasmania. So in those regions the gaps will not be as large to make up for those big stretches with very little and hence for most riding there there may not be as big a difference in being to buy food along the way most places (and more densely populated than parts of Nevada or Texas or other western states I've ridden).

So my comparison would be that Northern and Western Australia has stretches that are more remote than I've seen in lower 48 states (and for that matter along the main route across Siberia) but that doesn't necessarily mean most who cycle there are in those empty spaces...