NBN is a monopoly so it has to be either State owned or State regulated in pricing ....take your pick because there is no competitive pricing mechanism to regulate price. SOEs are designed as public services, not as profitable businesses.. eg: policing, armed forces, transport & communication infrastructure etc etc etc.
There are over 2500 corporations listed on the ASX and hundreds of thousands globally for punters to invest in.
We saw Medibank Private privatised which resulted in subsequent enormous rise private health insurance premiums.
The purpose of Government is to ensure the General Good....not the profits of a few and for monopolies there are 2 options: -State owned -State regulation of pricing