Membership numbers are a stupid stat to compare NRL vs AFL support. My kids did a 10 week Auskick program through their school, and where automatically made GWS members for the year (even though they have never been, or likely will go to an AFL game).
Viewership is pretty even between the two codes, but finals viewership probably suffered this year for the NRL given the most followed clubs didn't make it (Broncos, Souths, parra, etc.).
Qld or even NSW becoming AFL states aligns with Victoria becoming a NRL state.