The whole concept of citizenship is a joke.
Citizenship and restrictions on immigration only exist because of the voting population who are too stupid, lazy and incompetent to make themselves valuable in any way, and know that in an international labour market, they wouldn't be worth dirt, so they jealously guard their ill-gotten wealth, acquired through the luck of happening to be born in the right place, with a righteous sense of entitlement.
If you are hard working and intelligent, you have nothing to fear from the abandonment of all immigration law, opening the borders.
The skilled and educated will of course profit greatly from the abundance of cheap labour.
I have no doubt that the conditions and pay of australia's working poor would be significantly undermined by the abolishment of immigration restrictions. However the conditions for millions of new immigrants would be substantially improved, I have no tears to shed for the minority who will be worse off, just because they happened to be born here and feel they are entitled.