The founder of one of Australia's largest independent ISP's Internode (and later NBNco board member) Simon Hackett put it very well in 2011 where he showed locking in a arbitrary $20 charge per megabit hobbled the network.The whole profitability revolved around charging more for faster speeds/more data in the future.
Every other technological advance gave users faster for cheaper whereas this network would only work if people paid more. Cut to the future and now you've got competition from 4G cellular data at the low end and private companies providing private fibre/wireless networks at the top end. The whole pyramid is coming crashing down so much that the government has had to introduce a new broadband tax ($7.10 per month) to subsidize it.
And even the tax won't solve the problems because the CVC usage charge still exists and the business case still resolves around charging more in the future. In about 5 years when they realize what a stuff up it's been we can only help they write it all off and we can go back having affordable fast internet like the rest of the world.
https://simonhackett.files.wordpress.com/2013/07/commsday-w-...
https://blog.internode.on.net/2011/07/21/nbn-retail-pricing-...