Think its would be more to do with Sky money.
Having 1 kiwi team in competition offers the FFA a whole extra revenue stream. Adding more teams from NZ wont be adding a lot more in terms of money they get from sky.
And why would they choose another NZ city when they have other bids sitting in their own backyard?
Saying that I would love an annual Waitangi Day derby game, even if it would always be an away trip.
I agree, I think one day Auckland will have another A League team. It would certainly be a big boost for local players seeking a pathway to a professional career and the Phoenix-Auckland derby aspect would be great. However it would need someone with deep pockets. There would also be the thorny issue of the O League, which is currently the lifeblood of the ASB Premiership. Where would this leave Auckland City, unless it became a feeder club for a new A League franchise? Don't see anything happening for another five years.