A natural monopoly does not exist for carriers, a natural monopoly does however exist for infrastructure. Eg it is more efficient if there are lots of carriers eg optus, telstra, etc etc however it would be widldly inefficient if there was lots of infrastructure eg your house connected to eight different copper networks.
As it stands the retail division of telstra forces the wholesale division to act in a way contrary to wholesale's interest but in retail's interest. Eg charging more to third parties than to retail for network access, not upgrading network infrastructure etc.
Thus the best solution is seperating the retaila and wholesale divisions of telstra and privatising the retail division. The result would be a wholesale company controlling all of the former telstra's infrastructure. This company would now be able to respond to the market demand for infrastructure rather than just telstra's. So we would see ADSL2+ etc rolled out quicker. The govt would be able to fund infrastructure upgrades were they neccessary/forced to by the nats. The retail division meanwhile would now be competing on a level playing field with all the other carriers.
The final result beng better infrastructure being upgraded quicker and lower prices for the consumer.
