BNEA320 raises a good idea and granted, it can't happen 'today', it should be discussed without attacking the messenger.
London City, circa 1500m & a single runway at that, does a magnificent job with less hardstand than Bankstown. Why? Because they want to. They need to. But so do we. With a city population of around 5 million our single RPT hub goes up against London's 5 major city airports for their approx. 9 million people. In fact if you choose to call yourself Sydney Metro Airport, how's about getting into the 21st century and delivering a world class feeder secondary airport that makes traveling to or from Sydney a market leading experience. Its high time the common-wealth of the nation was regarded as just that, and infrastructure assets such as capital city secondary airports were made to participate in an integrated air transport system. The government of the day must bring on board the current consortium of owners to either develop or get out. A very fast rail link from Mascot to Bankstown to the new Badgery's Creek airport will mean a somewhat future-proofed aviation system of which we can be proud.
If you ever wondered why this country rarely gets out of first gear, despite its good fortune, there are defeatists' from the early stages of this thread that may help you identify the cause.