Sir: Oliver Friendship raises some important issues relating to the ageing of the Australian population (“Our Ageing Population and the Constraints on State Power”, April 2021). He notes, correctly, that higher immigration cannot realistically solve the issues associated with an ageing population. While the “Big Australia” lobby continues to claim that higher levels of immigration are needed to combat population ageing, the unavoidable reality is that immigrants grow old too. Higher immigration has almost no long-run effect on changing the age structure and simply increases the total size of the population. This creates bigger problems in the future. The infrastructure…