Yeah, savings and/or investments are going to be the key.
That said, if I did have enough money to retire to the homeland, I don't think I would. Assuming one is not on the run from the law, living this long as an expat says something about lifestyle preferences. I for one love Australia and all, but living there feels like a chore. I might change my mind as I get older, but I have lived in Adelaide, Sydney and Melbourne already, and visited a few other capitals, and while the air is so clean it's almost harsh in its purity... eh, I don't know. But yeah, if I did have enough money to retire to the homeland, I'd live large in South East Asia instead. Big house, no neighbours, a beach nearby, be discovered one morning by the housekeeper and what do I even care by then, dump my carcass under a tree. This is my fantasy.