Australia's sports capital?

Many people say Melbourne is Australia's sports capital but the majority of sports played in melbourne is at the MCG think about it? Socceroo matches are played there, AFL and Cricket. The telstra dome is only used for afl. and that's it. I think Sydney is very underrated as being the sports capital of Australia we have three main stadiums used for different sports. ANZ stadium is used for rugby league, occasional Cricket and AFL as well as soccer. The Sydney Football Stadium is used for Rugby league and soccer and the SCG is used for Cricket and AFL. Sydny has much more variety so why is Sydney second rated to Melbourne. Is it because of the Australian open?? what other major events is held in these two cities??