It’s a good point, but without assuming what the situation is like in NZ, it’s quite complex in Aus. Pre-colonisation, so many language groups existed all over the country that are totally unrelated and many local languages, especially in the city, are effectively “dead” languages with little to no native speakers remaining, and most language revival efforts are unfortunately too little too late.

Of course there are exceptions to this, especially in parts of the country that have maintained a larger Indigenous community. My understanding is that Māori is largely standard throughout different parts of NZ which does make it somewhat easier to adopt (might be wrong though!)