I've really noticed this in Brisbane. A lot more talk about NRL at work and with friends from school (Rugby school, not traditional league supporters). I've been seeing NRL apparel EVERYWHERE as well.
My theory why -
1. Super Rugby is basically dead (in Australia at least) so we've taken most of their supporters. Red's used to average 20 - 30k, Waratahs 35k+, Brumbies got 15-20k. They are currently getting about 1/3 of that, maybe even less. Where have they all gone? NRL.
2. The NRL has really cleaned up its act and is more attractive to a non-traditional audience. Not too long ago a lot of people thought Rugby League was a thuggy sport watched by bogans. Off-field dramas are much less, thug-like behaviour on the field has been stamped out, NRLW would have helped and the addition of 'higher class' sponsors have shed the low-class stereotype the NRL had and have made it much more attractive to upper and middle-class fans.