It is astonishing that Vodafone , which is having the most problems with capacity, infrastructural and in-home penetration of their signal, is the one that is saying they have enough spectrum and don't need to buy more!
I am one of their customers and when 4G become the norm in 1-2 years time and my contract is up for renewal, I will careless what Vodafone says, if their 4G network is not up and running and is fantastic (speed and reception in doors and out) then moving to another carrier will be what will happen.
I will be presently surprised if Vodafone is still around in Australia by 2015, they are simply not putting enough money and forward investment to meet current and future demand and expectations.
To me it seems they are putting just enough to stay around until maybe someone buys them off? not sure who would do that though.....