I think some clubs can get to the point where on field form has less of an impact on their crowds, but it is reliant on them building a good game day experience, growing membership and arguably creating some scarcity around tickets.
I agree with the points about pricing, membership, game day experience, etc.
Don't you think though that overall growth depends on the fanbase regarding wins and losses as merely one element of the experience, rather than the be all and end all?
Pessimism would be forgivable if your club were getting spanked every week, year after year, decade after decade.
The salary cap does its job. Every NRL team and game is potentially competitive.
Sharks are top of the ladder, yet lost 0-42 at home last week. It's in the nature of modern RL that such a defeat can happen to any team, whatever their position on the ladder. Means nothing, long-term. Just inevitable ups and downs of a strong and healthy competition.