They won't replicate the Dolphins due to diminishing returns, but they will be strongly attended and viewed. The NRL knows it and the broadcasters know it.
Besides, the reason to do it isn't for their crowds and viewership in year 1. The reason to do it is so that in 50 years, the NRL has grown with the expanding SEQ market and kept itself as the # 1 game forever in all corners of our region and at the same time suffocated any opportunity our competitors had to grow.
The Lions and Reds don't know how good they've had it since the SL War, it's a crime we've given them so much air. Good to see the NRL focussed on squeezing the life out of them now and growing our code. And yes, growing with an expanding heartland is growing the game.