Why...
By all accounts he has love life down under and has a great friendship with Ball and Taylor going on. NZ is a far safer place than Europe is at the moment, and bar for his injury now, he also probably realises that our 1 game a week season is good for his body etc.
Having played at the level he has, for as long as he has, financially his next move doesn't need to be about the money (although that clearly should be a consideration)
Because of the massive uncertainty of how A League 2020/2021 will shape up, and the Nix being a NZ team in an Aussie comp.
Another hub in Aussie that worst case could go, out to July 2021?
Whilst his family are living where, the UK or NZ? That would seriously suck.
Meanwhile the EFL Leagues start next month, and he will be on the radar of some UK clubs, where he can have his family in a stable environment - plus maybe still earn close to $NZ1M or more per season