The Australian video game industry has always been a bit boom or bust. We had some great stuff going on in the late 90s and some great titles coming out, then a bit of a downturn during the dotcom bubble burst.
But when that happened, one USD started buying two AUD, and a lot of US companies started setting up studios in Australia. They had a few good years, taking advantage of the cheap cost of labour thanks to both leveraging the exchange rate and the enthusiastic and excellent Australian staff, but once the AUD starting doing well the benefits started fading. Studios shut up shop and vanished with barely any notice.
There's a lot of awesome Australian talent scattered over the globe now; most of the people I know who were serious about the industry decided that if they wanted to make a reliable career out of it they needed to head stateside.
Now the AUD is waning again it's possible we'll see some more American dollars going into it, but it's easier than ever for US companies to bring Australians to the US, so I suspect that's more likely.