I heard of one 738 skipper returning early from such a contract. Until mainline attrition actually starts to rise and causes a shortage in mainline, there is no leverage possibility in respect to the mainline eba.
A sample of one pilot?
Might need a bigger sample as Australian exceptionalism aside, pilots are a globalised commodity. Isn't the campus a place of knowledge?
Might want a more robust sample before generalising that Australia is somehow immune. Ask your masters at the subsidiaries how many qualified applicants they receive, ask about the other entities.
They will quietly confirm that there is not the supply there once was.
You may be right, pilots in Australia may choose to ignore the global demographic elements at play in the structural shortage.
Perhaps Elon Musk can deliver a driver less aircraft by 2020, when apparently living on Mars will be commonplace!