The State of Domestic Cricket

I often hear people say that the Australian domestic competition is by far the greatest in the world but why is this so?
Is it because Australians are the biggest cricket fans in the world? Maybe, but then again, maybe not, Indian cricket is a "religion" in India. The Barmy Army have showed us that the English are passionate about cricket.
Is it because our domestic teams have greater funding than others? maybe, I don't have any figures to be able to say for sure.
My theory is that because Australia has been so dominant for so long the "fringe" players have to be better just to get a crack at playing for the national team which in turn means that most players have to be as good or almost as good as the fringe players just to make in to the state team. What's your opinion?