Exactly. All this talk about how far by car or train to WSI for Sydneysiders at the moment. Does anyone actually think that with the airport growth, the public transport won't expand? Just like it did for SYD? And the concept that Sydney airports are just for Sydneysiders is pretty lame.
Many of us in regional areas, or even smaller capitals like Adelaide need to fly to one of the east coast cities to begin international. At the moment, I avoid SYD like the plague - the Dom-Int transfer, the old infrastructure etc. I would fly in and out of WSI over SYD any day and as I've said before, I think airlines will encourage use of WSI by fares and scheduling. Core services at SYD (with some slots opened up by moving non-core to WSI), lesser demand flights at WSI, but possible scheduled connections.
And the noise and environmental consequences? The population density around SYD means that it will never be expanded nor things like Bankstown expanded (I know nothing about that airport, other than it exists). Considering the cost, traffic congestion, noise and everything else, no government would approve an application by SYD airport to expand. They would simply say "WTF - what are you thinking? We've got this new international airport at WSI, with expansion built in. You were offered first right to build and develop it, but you declined. Tough."
