Good luck finding someone willing to pay to have squillions of kilometres of above ground power lines buried.

Sydney alone has 63,000 kilometres[1] of overhead power lines. One estimate puts the cost at $23.37 billion.[2]

1. http://www.smh.com.au/articles/2002/07/29/1027926858231.html

2. https://www.ipart.nsw.gov.au/files/7b5531d9-cf65-4b1b-ae7b-9...

Some places even managed to get entire sewer systems buried. Granted, that happened on a very different level of urgency (you really want shit to flow, and it only flows downward), but it gives the appropriate perspective on any excuses that are based on the natural scale of infrastructure.

Is not a good analogy since nobody builds a sewer system above ground and then replaces it with one below ground.

The point is that for sewers there was no choice so we just swallowed the cost and got on with it. For power there was so we went for the cheaper less reliable option.

According to your citations, that figure is for all of urban and suburban Australia, not Sydney and would be spread out over 30-40 years

That'll learn me for skim reading and cherry-picking to suit my narrative.

It's easy enough to do, at least you cited.