A few points in response to this.
First, broadcasting revenue only makes up something like 25% of the ARU's revenue, and a lot of that is for test rugby, which wouldn't change. Second, we have no idea what broadcast revenues a proper length, well-scheduled, Australian market focused professional competition would generate, especially in the longer term. Third, even if it's a fair bit less than Australia's cut of Super Rugby broadcast revenue, the costs of such a competition would be substantially lower.
Everyone's so hung up on the revenue side of things, but look at the costs, the ARU are spending so much every year to prop up a failing competition, on corporate expenses and on central contracts in what is a futile effort to keep our top players in Australia. The reality is that the salaries in Europe are growing faster than the salaries here. The only way this might change is if rugby were to become a hell of a lot more popular in Australia, and perhaps Asia. Neither will happen by sticking with the status quo. And if it never happens it may be better to at least have a competition that the rugby community across this country, in all major regions, can engage with and support week to week. Whether that be as big as the NRL or the NBL.