I don't why people bang on about overseas models when the best model and certainly the best model for Australia exists here in Australia.Thats because its big business, and competitive. American state governments give huge incentives to businesses to base themselves in those states, including sports teams.
The U.S.A. is the same size as Australia but has 50 states. It has 300 cities over 100,000 population but only 10 cities > 1,000,000 population.
That leaves a lot of scrambling for a national league franchise.
In comparison Australia has 6 states and 5 cities > 1,000,000 in population.
Australian cities have maximum use of their stadia. Football every week in winter and cricket in summer. Plus cities have teams in multiple codes.
It is the the most efficient use of stadiums in the world and that's why Perth can afford $2 billion for a new stadium.
The NFL doesn't even have a true league (my our standards) it has a conference system based on 4 or 5 team groups.
They don't have the situation where a team flies out of Perth every week to the other side of the country.