Every Pilot in AUS/NZ knows how seniority driven the Airlines here are. Especially the Legacy Carriers.
Some chose to chase the money and progression abroad, some slogged it out in GA/Regional's waiting to get on the Seniority list ASAP. Others (like myself), took a halfway approach and kept a current C.V. in back home and raced back the moment a job was offered, turning down a Command in the process.
We've each made our beds in Aviation, and we need to accept that.
In all reality, DEC's likely will get offered in AUS at some point in time, they just wont be at QF.
Talking to those who have (or are currently) doing the Expat gig, there's really 2 "Windows" to come back home to a Legacy Carrier. When you're young enough (Early 30's) to still have a decent Career back home, or when you're old enough (50+) that you've gotten the LHS out of your system, the Mortgage paid off and the Kids moved out. I've met a few late in life S/O's who really don't care what they earn now, it's all about the Lifestyle.
Unfortunately, a lot of guys try to move home in their mid 40's because the Wife/Kids are sick of China or the Desert, but that's about the worst time to move.