You probably know this but for anyone that doesn't understand the relationship between NBN and ISPs is that NBN are a Wholesale provider that are not permitted to deal directly with end (retail) customers. ISPs buy bandwidth and household/business connections from NBN. They then package that up into their own offering at retail prices.
There were a few providers that had their own fibre networks servicing mainly large corporates such as Amcom Mainly to CBD streets. Although Bright Telecommunications in Perth at one time laid optic fibre in residential South Perth streets as part of putting overhead power cables underground.
You can swap (churn) isps but the FTTP or FTTN is NBN property.
Abbott tried to kill the original NBN because it was a threat to Murdoch business. Foxtel movies were getting competition from the likes of Netflix.
