The stats don't support you there Coochiee, for a number of people the nix are their second team, and there are half a million kiwis in Australia (you being one of them) some of which support the nix, of course that's all hearsay.
The facts are that the nix rate about the same as CCM and the Jets despite not having a domestic audience so people are watching them despite the fact that they aren't their primary team, we're also are not anywhere near the lowest ranked game for any team that we play and in fact IIRC we were the second highest attended home game for the Victory of the year when we went on a big run. The above seem to show that there is a reasonable amount of mind share.
The FFA don't owe NZ anything, but they did make a commitment to Oceania on leaving to have a professional team in the competition for ten years. Which has of course expired.
Ultimately it needs to be a mutually beneficial relationship, the FFA are talking expansion and Auckland is by far the biggest untapped urban market, Auckland CIty has also made it their mission to be in the A-League within the next few years, and they are a pretty well run club so I'm sure they can put together a credible bid. The FFA are also talking promotion and relegation and there is no way they can get enough clubs together to have two pro tiers.
What people here (and in Australia) don't realise is that Australia has a small population with a very large land mass, it's not a big country at all. I lived in Moscow for a bit which is only a few million people shy of the entire population of Australia. Despite having a tiny population they have a shark load of professional teams (as do we). Any city with more than a couple of hundred thousand people will have multiple professional sports teams, if you compare that to the US then a city like Austin with a population of 3.5 million only has minor league and college sports teams and nothing which is fully professional.
Australia and NZ (and probably the UK) have to be the most crowded sports markets in the world. They just have no room to grow to the size that they need to be domestically.
Another way to look at it is this, I count at least 18 professional teams in Sydney (9 league teams, 2 AFL teams, 3 cricket teams, 2 football teams, 1 basketball team, 1 baseball team - and there are likely more), at a population of 4.3 million people that works out at one team per 238,000.
By comparison Auckland has 5 professional teams (4 Rugby (although I think some Counties and North Harbour are players are semi pro), 1 cricket, 1 basketball) with a population of 1.4 million works out at 280,000 people per team. But most importantly there isn't the same level of variety of teams to compete.
Of course they don't owe us anything, the relationship has to be mutually beneficial. But if Auckland City with their track record put together a bid they'd be mad not to consider it.