Just some exclusive market comparisons:
Knights = Newcastle, Lack Macquarie, Hunter = 700k (1.1 million if you include Central Coast)
Titans = Gold Coast (640k) and Richmond-Tweed (260k) = 900k
Cowboys = Townsville (260k) and Cairns (250k) but really they were the only local alternative to the Broncos for decades. So it's between 500k - 1million - depending how far south you go.
Raiders = ACT = 454k (not including Southern NSW)
Dragons = Illawarra (314k) + St Georges district
For comparison:
Sharks = Sydney-Sutherland = 230k
Sea Eagles = Sydney-North Beaches = 265k
I think this is what codes like AFL and people in Sydney don't get. Some of the NRL's regional clubs are already bigger than Sydney NRL clubs. If clubs like the Sharks and Sea Eagles don't expand outside their enclaves, the gap will grow wider. And codes like AFL will never appeal to areas like Newcastle unless they put local clubs there (which if they do, will be bigger disasters than GWS/Suns).