Dumbfounded

Try and book a domestic flight within New Zealand with Qantas and your redirected to Jetstar.
How & why is Jestar (subsidiary company of Qantas) allowed to fly domestic within NZ?
The Australian Government reneged on a deal to allow AirNZ to fly domestic within Australia?
This was the whole point of AirNZ buying out Ansett, for AirNZ/Ansett to fly domestic within Australia.
Sometimes I wonder, flying with AirNZ/Ansett rather than Jestar or Tiger? ? ?
I know who I'd rather have preferred. . .