I'm not sure about Melbourne, Fuss, but the Brisbane Roar have sold out Lang Park for 3 Grand Finals, something they don't come close to achieving in the regular season.
Speaking strictly for myself, Steve, (and with no affiliation to the FFA or Europe), I played football from the age of seven - and that was a long time ago! I remember the thrill of playing in my first semi final, and of winning my first Grand Final. It is simply something I have been brought up with. I'm not particularly concerned about where a finals format comes from and acknowledge there are all kinds of different formats around the world in a variety of sports.
Funny thing about the FA Cup (and probably good for a whole article); it has suffered in prestige since the establishment of the Premier League and the Champions League. In essence, the Champions League has become the money-spinner needed to stave off the rumblings of a European Super League which existed in the late 80s and early 90s.
There was a time when the English FA Cup final was the most watched football game worldwide annually. Clubs never played "2nd XI" sides in the tournament and there were ties that went to 4 and 5 replays. In today's crowded schedule, that's clearly impossible, but in my opinion, the Champions League has become the ultimate artifice - a competition that can only be won by clubs from Spain, Germany, Italy or England.