Literally the next 2 listings on that site show a rate of 250 AUD/hr instead of the 200/hr jobs you posted.
First
Second
That particular company also seems to have lower paying jobs than others out there.
Looking quickly at other locums sites such as Here shows that ED docs make 250-500k / yr there, which is comparable to US salaries. As to your statement that the VA will "100% guaranteed" drop pay if everyone has to work for the VA... that might happen, it might not. The salaries for NHS docs would seem to support that argument. Salaries in Canada and Auz (as I just illustrated) do not.
Thank you for using...evidence! There are insanely low-paid locums in the US, also. I get emails regularly offering $100 an hour for "easy" jobs. I think folks have a hard time accepting that Aussie docs might have the best gig of all.
As I'm sure @Birdstrike knows, the NHS has such a hard time staffing their ERs that locums pays well over £100 an hour. And that's for weekday, day or evening shifts. Oh, and the hospitals have pubs.