This article from ALPA cites the importance of scope clauses and ALPAs collective bargaining power;
https://public.alpa.org/portals/alpa...2003_Scope.htm
The problem with Australia is that each airline has its own union which means any coordinated move by pilots to regulate terms and conditions is restricted to each company at a time. 1989 showed that when one union goes out on a limb, the union that felt it had nothing to lose just watched and let it happen. Without getting into the politics of that, ALPA has always represented a huge majority of US pilots and as such scope clauses are relatively easy for them to negotiate and apply to a number of airlines at once. Yes having your own union does mean you focus on particular company issues, however a strong large union can prevent degradation of conditions across a number of workplaces. Maritime unions locally are an example of this.
Of course if one union goes up against its own company for scope it will get rejected out of hand, that's so easy to see. Threaten the whole industry with walk out if scope is not implemented, now you get the attention of the top players. What bargaining power did a QF pilot have in the 90s? AN had just squashed the 89 rebellion dramatically using government support, that would be pretty fresh in the minds of pilots and management. Of course anything that hamstrings a companies ability to be flexible will be rejected out of hand.
Some quotes from the article;
Capt. Woerth told ALPA’s Executive Board in September 2002: "We will never be able to stop the race to the bottom in every economic downturn or to stop competing for jobs within a code-share alliance if we don’t get some degree of control over what the terms and conditions are for qualifying for a code-share.
"I firmly believe," Capt. Woerth said, "that if we coordinate our joint campaign for this next-generation scope, which involves more code-share governance [and] puts as much or more emphasis on the quality of the pilot contracts involved as in the quantity of aircraft types permitted, then the profession and every pilot in the code-share arrangement will be better served."
First Officer Ron Abel (United), BSIC co-chair, says, "Scope is an important and necessary tool for protecting our jobs, but it cannot be truly effective unless pilots within an airline system understand that all our jobs are at stake if we don’t work together to provide scope protection on a system or global basis.
"No one should pretend that the way ahead will be easy," F/O Abel says, "but drawing lines around each pilot group’s flying isn’t providing the protection we need for the whole system."
That last one really is what happens in Australia.