Originally Posted By: AZjeff
...why anyone would want more than 1 wife is beyond my understanding.
This +1.
Regarding the population increase, Australia has much less population density than the US or UK, which in turn have much less than say India. 25mil doesn't seem like a big deal to me, we have more than that here in Texas alone, and there are still vast empty spaces in many parts of the state, especially the western half.
Regarding the immigration, people who come to a developed country need to at least follow the laws. As for following cultural/societal norms, that's 50/50 at best. Ask me how I know, my wife is Brazilian.