A nation that has learned to extend life now grapples with the quieter question of what sustains it. Australia's Treasury, peering four decades into the future, finds a people living longer and growing more slowly — women approaching 90, men nearing 86, yet fewer children being born to carry the story forward. The infrastructure of care is working, but the economy of the future rests on a technology — artificial intelligence — whose promise and peril remain unresolved, drawing Australia into a global conversation about how humanity governs its own inventions.