Canada which has a similar colonial history to Aus ( with exception of Francaphones) has 50% higher population than Aus , driven by Immigration , It is in the G7 while all we can muster is being # 17 in the G20.
Will we ever get into the G7? IMO no unless we grow our population like Canada. By the way Canada is much bigger land mass than Aus and it is more densely populated than Aus
The old argument that we have a desert middle does not stand up either because even Canada is much bigger than Aus, Aus has a greater amount of arable land .
