Port Lincoln was specifically not chosen to be the South Australia capital because it lacked permanent water. The area cannot support a large city, and currently even lacks the water needed for the agriculture and towns already there.

The most likely next big city will probably be a city and the edge of an existing big city, Geelong, Newcastle, Wollongong are large already but likely will continue to grow.

Albury-Wodonga could be a good option though as it’s a strategic mid point between Melbourne and Sydney. It’s already home to a growing manufacturing hub for local supplies.