NBN started with a FTTP to 95% of the population, new govt chose to redesign it mid rollout to stop all Brownfield FTTP and reutilise the copper to save money (the very crappy copper).
NBN FTTN is a VDSL2 service over copper or HFC both designs deployed fixed wireless and satelite to regional ares
1 difficult to do mostly a problem because consumers arent paying for the 50 - 100mbps speed tiers
2 Telstra is basically doing this already
3 this would require the current pm and previous communications minister (mal turnbul) to admit he was wrong.... it would also be a huge cost to go back out to all FTTN sites and roll out FTTP instead.
4 nothing changes because our pollies have spent the last 10 years playing "thats not a knife" (howard was the last full PM to actually serve his full term)