I highly doubt that the Melbourne proposal will go anywhere. The reason for that is because the people with money and power use corporate aviation in Melbourne. In fact they are pushing for Melbourne to take over Sydney as the 'premier destination' in Australia just by the sole fact you fly your jet in there and get a chopper to the city.
Those sort of people don't make any noise they just quietly get things done the way they want. If this proposal actually gets serious you will find surprisingly that Labor and Liberal Parties will come out against it as both will be lobbied by their respective big ticket donors.
If Packer managed bypass government in Sydney to get an entire Casino built on the some of the most sort after real estate in the world, I'm sure he'll be flying his punters from YMEN to the CBD for many years to come.