What about the Challenge Cup?
Different line ups every year and not seen anything like the same drop despite 2009 not including 2 of the best supported sides in the league at the time.
which is an interesting comparison..
every year till this year it was dropping, not by as much granted but still dropping. London is a draw in itself and there is a "weekend" culture around the challenge cup and a much more established culture.
the pick up in 2010 could be seen as a spike with leeds getting there and also perhaps a feeling of "well i havent been for a few years due to being skint" and so going again.
The line ups were different and yet the numbers were dropping so maybe the grand final is a mixture of the economic situation and the two similar teams.
They're not exact same situations as they are different cities and very different for RL as there is distance, romance, history etc in one where as the other is one big bang night.. but perhaps one an learn from the other or we can certainly see where issues are with one compared to the other.. certainly makes for interesting reading in comparison.