So much for Rudds NBN future proofing Australia, page-172

NBN is still needed to propagate/deliver the signals between wireless transmitters and core network. : The core network is "hardwired with copper and light pipes", passing through the MEC stage and several more stages before it meets the radio access network.

Light pipes to the premises was a huge ask, but highly adaptable to change. Wireless has an historical habit of becoming redundant requiring new phones, new laptops, new plans, etc. a cost people conveniently overlook when spruiking CBA.