It really is location dependent. A Sydney club servicing 4 NRL clubs, an A-League club, a Super Rugby side plus hosting other games like finals, rep matches, concerts and other events/functions could.
A NSW NRL stadium is a must and a good revenue stream.
In qld Suncorp stadium would be similar. 2x NRL teams, origin, a-league team, union team plus league and union test, concerts.
Something else that I think could be another way to improve income streams and that is get each club to video and document the work they do with children's cancers/diseases.
It could be a 16 week - 1 hour a week (1 club per week) series of children that are suffering and each team documents the story.
A year or 2 ago the storm and Erin molin did a documentary on a little girl who was battling cancer or something like that and it was very touching and would appeal to the general public.
Could run the series at the end of the season and could help boost memberships.
The NRL could shop around for the channel that wants to broadcast it.??