I think that The US's experience of wireless broadband demonstrates the dangers in relying on private enterprise capital and regulation to deliver a functional long term backbone of infrastructure. The article I've linked to demonstrates the pernicious effects of selling responsibility of infrastructure onto the private sector. The value of a spectrum increases if more can be done with it, and therefore there is an perverse incentive for government regulators to relax spectrums and rules, independently of the original reasons to have the rule there in the first place. It isn't just a "fibre is better than wireless tradeoff". Wireless is always going to be chosen by private enterprise because a return can be made in a reasonable timeframe. The issue of fibre vs wireless is separate, and I would be just as happy with the NBN plan if it went something like 10% FTTP, 50% FTTN, and the remaining 40% the newer version of next G wireless, as long as the government could take control of the infrastructure.
However both for practicalities in taking over the infrastructure and being able to think long term, 93% FTTH is entirely reasonable in getting country areas onto the grid. The more important point to note is that Australia's transmission spectrum will remain functional and unencumbered by huge data loads and conflict of interest, while the US's will lose way more than the $1500 per household or whatever it is within a decade in its dysfunctional spectrum allocations and congestion.