I've been to some forums where they said that Tunrbull's NBN alternative isn't so.

My favorite question one forum member had already answered and I'm reposting it here:

A valid question on many people's minds: Why not re-use the HFC networks already built ???- it is crazy to shut them down!

Answer: Existing HFCs do not present a viable alternative. They only suit a short term solution (4 to 8 years) as compared to 30+ years of the NBN.