These statistics probably say as much about the Australian media landscape as anything else. Australia's media is quite homogenised and uncompetitive; a handful of proprietors have the mass media sewn up (there are two newspaper proprietors and about three commercial TV networks). The lack of competition has resulted in low standards of quality; for example, the Fairfax papers (The Age and The Sydney Morning Herald are the biggest ones) are generally regarded to be the "quality" papers, but compared to the British equivalents (such as The Guardian and The Independent), they come out poorly, heavy on the sex, sensationalism and celebrity gossip and light on content and analysis. (The effect gets worse as one moves away from Sydney and Melbourne; for several weeks a few years ago, the most-read story on the front page of Fairfax's Perth paper was "Man gets penis stuck in pasta jar".) Or compare The Australian (Murdoch's "serious" paper in Australia) to its UK equivalent, The Times: The Australian is more nakedly biased.
The Australian press, controlled by an incestuous oligopoly and not subjected to the indignity of competition, has become a stagnant pond. (Australian television, mind you, is much worse.) This is bad news for the kind of discourse required to sustain a mature democracy; a public fed simplified half-truths leavened with gratuitous doses of sensationalism will be in no state to engage on a meaningful level in debate about where their country is heading, leaving all that boring stuff to technocrats and vested interests. The internet provides some competition, but the alarming open-ended censorship firewall plans (all content "refused classification" will be filtered; this includes sites advocating euthanasia, illegal drug use (including offering safety advice) or video games unsuitable for children; the list itself will be a state secret, giving plenty of scope for other sites to be "accidentally" banned if convenient to do so) which look set to become law before the next election, leave a lot of scope for rival sources to be nobbled. (Not surprisingly, the Australian press has been quiet about the plans, echoing the official line that the plans are to "combat paedophilia" and are opposed only by some anarchistic extremists.) As such, it doesn't surprise me if Australia's press oligarchs make the most of their privileged position and cut costs by bulking their papers out with press releases to a greater extent than in more competitive markets.