Something which may or may not be a factor but is often forgotten re attendances at Melb clubs v sydney clubs is the relative health of the local A league clubs
The reputation and support for Melb a league clubs has really dropped off in the past 5-10 years and has coincided with a rise in attendances at traditional clubs.
Each city/state is its own distinct market re the a league and the perception of the comp varies from city to city. Imo the league hasn’t suffered as much reputational damage in Sydney or Adelaide as it has in Melb for example. it’s not as it was at its peak but it’s still ticking along fairly decently here. Without necessarily getting into the reasons for why that’s the case
So don’t forget you’re competing with Sydney fc and wanderers who get decent support, and then you’ve got, Marconi, APIA, Sydney Olympic, Sydney united..and macathur too (if they don’t end up folding). So 7 clubs playing at a national level simultaneously, that’s a lot of competition for fans and when you put them all together a fairly decent cumulative number of people attending and supporting local clubs in comparison to other cities