+xZlatan has stated things like the best players shouldn't settle for being comfortable in their surroundings and should always push to test themselves in new environments. I'm not so sure Melbourne would be the kind of test he's thinking of though.
He's also fairly well known for having an ego which makes Ronaldo look humble... If money alone wasn't likely enough to make sure that he'll never come anywhere near this league, I think prestige would make extra sure of it...