The old "obsolescence risk" keeps arising, but is hardly a serious risk. The passive optical infrastructure - the bulk of the build - is good for anything that optics is capable of.

NBN Co has qualified its switches for 1 Gbps, but even this is very conservative. In 2001, the Southern Cross submarine network had 60 Gbps capacity; it now has 1.2 Terabits capacity on the same cable.

Alcatel-Lucent has demonstrated lab systems performing at around 100 Petabits / second over short distances. So in terms of capacity, the most valuable part of the infrastructure - the fibre - has plenty of room to grow.

As with the ABC before the current Managing Director completed the destruction of its internal production capacity, or before the flog-off of QR National transferred its focus from operations and training to maximising directors' fees, or the flogging-out of TAFE education destroyed it, NBN should be using essentially its own workforce, paid and comprehensively trained by it.

Government services often have simultaneous operational, economic, social and/or environmental objectives. So public service delivery often needs to be considered within a broader context than do profit-seeker or NGO service providers .

Australia Institute has made the point that for decades government-owned enterprises were instrumental in training generations of skilled tradespeople. When workers finished apprenticeships, some would stay, while others would be poached by a profit-seeking sector that profited by not training (like Big Mining today).

Funder-purchaser-provider (on which contracting-out/flogging-out is justified) is an evil ideology masquerading as economic theory. It is one part of the ideological framework of transnational capitalism to privatise profit, socialise cost, and in addition reduce public spending from which it doesn't benefit.

Most likely it is simply finances. Speeding up install means more capital out with less time for revenue to come in. The government should have set up a trust account, where customer could pre-pay broadband for a discount and to trigger a priority roll out in their area when sufficient subscribers in that area are achieved.
You now have revenue in to reduce capital demands and of course a subscriber base is achieved.
This also allows direct promotion of the NBN, as ISP/Telecoms strive to gain pre-order, the funds of course deposited in the trust account and only available when those connections are actually provided.

The reality is the NBN will become a huge white elephant. Everybody seems to have forgotten about a company called Davnet and its business model in the dotcom boom.
It is this business model that will bring the NBN undone.

I recently had the joy </sarcasm> of compiling the registration documentation to allow the college at which I work - and my domain is possibly a giveaway - to deliver qualifications from the new ICT training package, ICA11. Part of this process requires engagement with relevant training councils and industry bodies to ensure that what we offer is what is required by the nation. The greatest focus from the national and state bodies was unashamedly on two skills shortage areas - licensed telco cablers with strengths in fibre optics, and ICT project managers, at the diploma and advanced diploma levels (and specifically NOT at the degree and higher levels, interpret as you will).

I suspect that these shortages, more than politics, are the real cause of the glacial speed of the NBN rollout.

With the state-led dismantling of TAFE demonstrated in Victoria and forecast to occur in Western Australia from 2013/14, these shortages are not likely to be addressed.