It's not just GA pilots QANTAS can call on, what about all the Aussies flying overseas who want to come home ? Many of them qualified on the types QF operate. And foreign pilots who see Australia as a desirable place to live would be here in a flash given a work permit.
Add these to the remaining QF pilots who would sign a "take it or leave it contract" and you should have enough to be going on with.
I'm not saying you guys don't deserve your conditions, dragging them down won't benefit me in the least. Geoff does have supply on his side and there are plenty who would grab your jobs without a second thought. Plenty of CX S/Os moved to QF a few years back when there were vacancies.