Immigration numbers aren't pulled out of a hat. There are a lot of factors like skill shortages, demographics etc taken into account. We could reduce numbers but we would need to do it carefully and plan for the consequences.
One Nation's concern about immigration is entirely a dog whistle for racial intolerance.
For shits and giggles the govt should announce a return of White Australia policy and doubling the intake and watch ON implode. Of course bringing out 10 bob poms to work in factories is fucking hopeless now we have shut them all down. What are they going to come here for? The skin cancer?