Charlotte sort of already addresses this, but just to clarify/emphasize: the fact that prehistoric Australia, with its low population, faced long-term economic and technological (near-)stagnation doesn’t imply that adding a person to prehistoric Australia would have increased its growth rate by less than adding a person to an interconnected world of 8 billion.
The historical data on different regions’ population sizes and growth rates is entirely compatible with the view that adding a person to prehistoric Australia would have increased its growth rate by more than adding a person to the world today, as implied by a more standard growth model.
Charlotte sort of already addresses this, but just to clarify/emphasize: the fact that prehistoric Australia, with its low population, faced long-term economic and technological (near-)stagnation doesn’t imply that adding a person to prehistoric Australia would have increased its growth rate by less than adding a person to an interconnected world of 8 billion.
The historical data on different regions’ population sizes and growth rates is entirely compatible with the view that adding a person to prehistoric Australia would have increased its growth rate by more than adding a person to the world today, as implied by a more standard growth model.