I, we, everybody understands the role immigration has played in getting Australia to where it is today. I don't think the OP said we should STOP immigration, but rather CUT (reduce) immigration from where it stands today - regardless of the figures quoted by the OP.
Also, there are examples where immigration/living standards correlation is a fallacy. Japan for example. Couldn't be bothered to look it up, but there are probably many others.
