Dave,
Have you considered the possibility that professional sport is all about money? League is strong now because it was professional from the outset, and its growth was fuelled, not by tribalism (that was a result of its success, not its cause) but largely by poker machines.
The AFL was the VFL until relatively recently, but obviously it does have very deep roots in a large proportion of the country.
The ARU is, in the professional era, a minnow fighting for the scraps between two giants.
We would all like to see good growth, the grassroots doing well, and so on and so forth. Have you got any specific suggestions as to what the ARU can do about this? The major opponent for our kids also has the huge benefit of setting its own rules, and of course of dominating sports coverage on FTA in much of our nation, while we are virtually non-existent.
Rugby is a game that thrives in some countries, and not in others. We are one of the others, unfortunately, and the reasons are obvious. Most of us actually enjoy the whole buzz of running with the ball, that is why league is so popular.
Meanwhile, it our little shitheap, the rich get richer ( particularly in our most important heartland, Sydney) and the poor can go to play league.