How large is Rupert Murdoch's reach through News Corp in Australian media

Regardless of whether or not he holds a stake in them, nearly every Australian news entity from online publications to talkback radio exists downstream from The Australian (Murdoch's flagship paper). The stories they choose to report on are the focus of the news cycle, and the points they raise on each story serve to plot out the battleground. In political journalism this is even more prevalent, as journalists unwilling to toe the party line aren't given access to government press releases and must rely on content filtered down through News Corp and its contemporaries.

It's also worth noting that the ABC is increasingly beholden to the coalition government, who it depends on for its funding, and the coalition government is in turn beholden to Murdoch, whose power over the press keeps them in power.

Note, also, that the major competition mentioned in the linked article (Nine/Fairfax) is chaired by Peter Costello, former Liberal party treasurer under the Howard government. Balanced competition indeed.

edit: formatting

It doesn't matter how many eyes/ears you reach out to. You can have 5%, but if you can twist the arm of the advertisers (the ones who really keep your media company alive), to force them to advertise less on others and more to you (or cut them off completely), then you can slow & steady change the game by controlling the funding of your competition.

Yes this is a very simplistic approach, but throw enough 'junk food' out there, lower the level (gossip, reality shows)(trash tv a la Berlusconni) and presto!

Edit: I just remembered watching the movie Bombshell (2019), and if the depiction of the Murdoch family is anywhere near the truth, they are utterly disgusting (and complicit).