The point isn't degrees of greenness but the fact that it changes with each boom. It has already moved out several times in my lifetime and I anticipate it will continue to do so.
It moves out every time there is a boom.
This time round, it seems to be at that 15km point as mentioned by several. It keeps changing. Not that long ago (25 years), inner west stopped at Annandale.
I wonder what kind of response you're looking for.
You could enjoy the richness of the experience or you could go on lamenting that your fantasy bubble has been burst.
What school did you go to in 'the north'?