PNG isnt being added for its value to tv lol.
If the Govt wasnt throwing an obscne amount of money at the NRL there would be no PNG. And the NRL is hardly throwing itself at NZ2 is it? Perth is only being considered due to Cook's funding and a chance to resurrect a dead Sydney club.
As I said above I dont think any locations really add huge value, Brisbane2 only added $20mill a year (not all cash), and that was largely to get Broncos off FTA, not to add any real value in of itself.
There are many other reasons NRL should expand the comp to new markets, but TV will be driven by competition for the rights, not by location of new teams.