Melbourne?
Yeah, by my reconing Melbourne has 10 AFL clubs, 3 A-League clubs, 1 NRL club, 1 Rugby club, and the rest like cricket, basketball, baseball etc.
Seems pretty comparable to Sydney in professional club numbers. The thing that makes it odd is the extreme regionalisation of NRL and AFL around those two cities, I wonder if there's anywhere else in the world that has that sort of clustering of sports.
It is crazy how competitive the Australian professional sports market is compared to other countries. The US is particularly sparse, Austin, for instance, has a population of more than two million people but no major league sports teams.