Then Telecom annouced the cabinetisation process, so unbundling exchange is completely meaningless after that...
Unbundling regulation came too late to be effective, if it was done in the early 2000's like Europe rather than 2006/07 a lot more unbundling would have been done by now and we'd all be better off due to increased competition.
The big delay for sub loop unbundling also created a lot of uncertainty and the decision on how backhaul costs are split from the cabinet to a pop between carriers in the cabinet is retarded. If I understand it correctly if their are 2 providers in the cabinet they pay 50% of the backhaul costs each even if Telecom (Wholesale) has 250/300 of the customers in the cabinet and the other provider has only 50/300.
Also it appears not all cabinets intstalled are the double size whisper cabinets with room for another providers gear, some are the single size ones and there is no room at all.
It simply doesn't make sense to build multiple sets of the core infrastructure eg: ducting for fibre, cabinets, exchanges.. for each area. I doubt the council's would give resource consent for multiple cabinets from different providers at the same location.
I believe Orcon stated the cost to serve a customer from a cabinet is 26% higher than from the exchange and it's not economic for them to do so.
Yes Vodafone and Orcon have stopped unbundling exchanges, but how can you blame them when sub loop unbundling is not viable and FTTH in the next 10+ years will change everything. When you invest in DSL equipment they would be planning for 10-20 years of life to get a reasonable ROI.