With the way the internet is evolving we'll want mobile services and not landlocked infrastructure (apart from a backbone).
Once the cable is in the ground, it will be able to cope with huge increases in bandwidth and speed, beyond what we can imagine even today.
If you go and spend 1/2 of the NBN spend ($25b) on a wireless network it could be obsolete within a very short time and require further investment.
So cable is future proof as it only required upgrades at each end of the cable (upstream and downstream). A wireless network however will require significant investment in technology all over the country and it will need to be upgraded. There is also a problem with the speed of wireless as the further you are away from the transmitter, the weaker the signal or speed you get.
And here is the next scoop for those pushing the wireless barrow.
Wireless providers (as in 3G networks) are already looking for off load to WiFi networks. In places were 3G devices like smart phones and Tablet PCs are common like say California. The Wireless providers (AT&T, Sprint and Verizon) are now investing in base station technologies backed up by Fibre to off load the amount of Wireless data being used, because even if they built a new tower ever 1 KM, the "air" is getting to congested with signal. Now that is for a high area of usage, but the first one to show the nature of the problem. There is only so much spectrum in the air, to many signals means no one gets the signal. 4G (3.5 actually called LTE) is the next step and uses a different spectrum but still will attenuate as people migrate to that as well so the problem only has a few years on wireless before it returns. Less if the amount of devices escalates as it has in the last few years.
While we all want wireless, it has to have a base station, and a national network for that is required. Even if we all get our own wireless base stations in the house with 3G cell ability, it still needs a back haul, that is why you use Fibre.
Also the fact that they use the name "broadband" throws people off into thinking it is Internet services only. If I renamed the current copper wire telephone system the NNN (National Narrow band Network), you could see that the connectivity can be used for many things.
I am currently connected to Optus via Coaxial Cable (the Hybrid Fibre Coaxial Network), that will be replaced by the NBN as is part of the contract with Optus. Even that network attenuates when used heavily because it is sharing the same cable and slicing off the network frequency to users (all users receive the message). That network as it is currently used is starting to have issues meaning no room for expansion.
The NBN will mean, my Internet, my Phone and more importantly my Subscription TV will all be coming to me via one small Fibre Optic cable, and not 3 larger Coaxial Cables.
How much did it cost to roll out the Telephone network. How long did it take? Was their a cost benefit analysis of that? This is the communications infrastructure network for the next century. Pure and simple.
