With regards to Perth/Adelaide, you only have to look at the Melbourne Storm. They have only produced a handful or less than a handful of juniors over the last 26 years. Perth may have developed a few more, while with Adelaide, the code would be lucky if one or two came through.
There should've been a second Brisbane team in the last 30 years, not the last couple of years. The NRL did miss out on alot players. With NZ 2, that is a question mark. Should they have come in earlier, and how would it impacted on the Warriors?
But for the overall bigger picture, the code missed out big time when it was part owned by a media company for 15 years. NRL missed out on millions of tv revenue because in rights negotiations, it was negotiating with itself.
For 15 years, News was making money, while the code was sitting still. If only the game was independent right throughout. Maybe more players would've come through to fill 20 teams. But we will never know.