So what happened to India, Pakistan, Fiji, South Africa, and the United States shortly after they became a republic?
Your very selective choosen historical examples is also flawed.
India/Paki, self rule after almost complete control from a foreign power that has a proven history of not putting alot of effort into border indentification and just drawing lines on a map (loosly at that). They have done the same in middle east.
Fiji, the reason they had a military coup and became a republic was due to the parailment being very heavily loaded with desendents of other countries on an small island nation.
In all of above, none of the local populations were in a position to properly manage their own affairs including dealing with different religious positions and other cultural issues and should have had a more progressive shift. None of these also compare to Australia at all and should be ignored from a common sense argument on the subject.
Sth Africa, Ok you want to compare Australia to the abolusion of apartide. Pls go ahead and demonstrate how this is relevent, note its civil lawless ness issues dated back before Nelson Mandela took over, it just was constrained more to the black areas where no one cared or reported.
USA, I believe the civil war was over their wish to have self rule and kick the British out! Australia already has this, it was done much later and more peacefully because the British knew they could not stop it and faced another USA style war if they tried but much further away and harder to support. The 2nd Civil war was about slavery, again please feel free to show me how allowing white people to own, control and whip black people taken from their home land aganist this will compares to this argument on Australia becoming a republic?
Most of the issues of failed/troubled conversions monachy to republic is usually due to internal battles for power after the withdrawl of a foreign/colonial govt and army in what is usually a developing country where long standing conflicts between different tribal and/or religious groups are often suppressed and/or the local population does not have the skills to run their country and own affairs despite beliving they do. The likes of Australia, NZ and Canada are not in this position mainly due to their respective finacial positions, small native populations and diverse immigrant population.