That was true even at the peak of the mining investment boom. So, again, the vast majority of Australians' economic lives are relatively unconnected to the biggest exporting sector. The past decade or so also isn't the first time Australia has seen a surge and reversal in the terms of trade, either.
The Korean War induced a boom–bust cycle in wool prices, a few years before Bert entered parliament. And just a few years after he left it, there was a surge in mineral commodity prices. This induced a boom in resource investment, though not as large or long-lived as the one we have just been through.