YSSY certainly has been where it is for a lot longer than I've been alive, but when Mr JW Howard decided to 'share the noise' because his electorate happened to be under the North/South runways, I suddenly got a heck of a lot more late-night westerly departures than I'd every had in all of my years living north-west of the airport.
I have zero sympathy for any noise complainers who decided to live near or under the direct N/S & E/W flightpaths within the previous 20 years.
What erks me is that the 'share the noise' philosophy means that I get frequent nights where the 'beat the curfew' technique has everybody initially heading west off 34L before they get on track.