It's not an NBN!
The COALition's "plan" should not be graced with the label NBN. I call it NNN - National Narrowband Network. By the time it is complete 25Mb/s will be considered narrow band.
Published statistics show that bandwidth usage world wide is increasing 50% per annum. The norm in South Korea now is 100Mb/s. The NNN will deliver 25Mb/s at best, expandable to maybe 50Mb/s with new technology. It cannot go beyond that except for the very lucky few because our copper network, on which the NNN is based, is old and corroded. Have you ever had a crackly phone call on an old land line?
The NBN (Labor) will start at 100Mb/s. The fibre will be ultimately capable of 10, maybe even 100 times that, with improved electronics developed in the next decade or 2. Consider this: Copper started at 300bps (0.0003Mb/s) in the 60's. When I started working in datacomms in 1976, the state of the art was 9600bps (.0096Mb/s). When the Internet became popular we all had 14400bps dial up modems. Then 28,800, then 56000. Then came DSL, a whopping 1Mb/s. Then aDSL at up to 20Mb/s, all using the old copper wires owned by Telstra. Note the "up to". That means under ideal conditions; perfect copper, very close to the telephone exchange etc etc.
Copper may have one or two more incremental improvements left in it. Smart people have increased its speed 80,000-fold in 50 years, but there is a limit, and we are just about there.
This is what Abbot and Turnbull would condemn future generations to.
Fibre, on the other hand, is at the developmental equivalent of the 300bps stage of copper, maybe 9600bps. 100Mb/s through a fibre is a miniscule fraction of its ultimate capacity. It is all limited by the electronics, the lasers and the detectors either end. They are going to improve out of sight over the lifetimes of the next 2 generations of Australians.
The COALition's proposal is today's technology for tomorrow.