The reality is that the AFL is only huge in Victoria and a few wasteland states whose combined population is less than QLD.
Quite a few of Rugby Union's so called top nations have fans and playing stocks concentrated in pockets of the country.
I am all for a Perth team and think it's a worthwhile long term growth exercise for RL, but the reality is, if you are as strong as we are in NSW and QLD and have a good niche foothold in Melbourne (and growing), you have a very good coverage of the Australian population.
The AFL would trade WA, SA and TAS for QLD in a heartbeat if given the choice.