Our footy, real football, came via Melbourne where some posh kid, Wills (?), sent to school at Rugby School, England, smooshed together a few different games resulting in our wonderful game. South Australia was one of the first States to run with it () and it soon caught on in the more forward-thinking parts of the country.
Sydneysiders obv.weren't as open-minded, or inventive as Wills (still ?!) and kept to rugby, as did some other places up that way. They all have a footy team though.
There are pictures of an Aboriginal game, Marngrook, that is said to have influenced Aussie Rules, and there certainly seem to be similarities...except Marngrook seemed to involve huge amounts of players!