This isn't really accurate... in fact it's not even close.
- First up, Australia has a population of 20 million, but only NSW and Qld have any genuine rugby footprint from a developmental standpoint (Melbourne and the Force are populated by NSW/Qld players, plus a few foreigners). That gives Rugby a population base closer to 10 million in Australia.
- Secondly is the fact that Rugby is minuscule compared to Rugby League and AFL here. From a developmental standpoint NZ and Australia have roughly the same number of adults playing the game. Meanwhile, Super Rugby is only available on pay TV, which has a penetration rate below 30% and frankly most people even in NSW and Qld just know very little about the competition. As a point of refrence, when the Waratahs won the Super Rugby ***le last year, the epic home final at Olympic park only got 3/4 full and its ratings peaked at 600k (compared with the 4 million+ that watched the NRL and AFL GF's each year). These stats are important, as it leads to my final point: money.
- Third, the ARU are basically broke. The TV contracts they get for tests and Super Rugby are quite literally one tenth of what the AFL and NRL earn respectively (current deals). In fact the game got so poor last year that they instead of pouring money into clubs and development, they started asking for money BACK.
So from a resources standpoint NZ is arguably better off - Rugby is the national game, has a very strong and long standing two-tiered national competition that feeds into Super Rugby and its is prominent in the school system. In addition, the All Blacks are a global brand with massive recognition, meaning their promotion rights go for quite a lot more. Moreover, I've also read that the government directly subsidises the All Blacks, something why doesn't happen for the Wallabies.