Rookie....
What do you mean by pretty limited? They still have all the opportunities available (in Oz) as they ever had albeit with a few years of invaluable experience under their belts, if they feel the need to come home. Or the middle east, or Asia, or basically anywhere. There's a big world out there beyond the Hermit Kingdom.
It's E3's today, but what if it becomes sponsored green cards in the future? Then they'll be in a position to get a taste of the big money. Might happen, might not happen. Who knows what the future brings? FYI with a 3-4 year command on offer at Frontier, Spirit etc, I think your pay estimates might be a little inaccurate if you think FO's in Oz (except widebody at Qantas maybe?) get more over here.
But by all means keep waiting for Qantas to call you up and offer you a seat in the meantime, while all the Aussies in the US are having a blast!