Ardern doesn't owe Hosking anything. And the long history of prime ministers appearing on the show is a tradition rather than an obligatory part of the job. She is well within her right to choose whether or not to speak to him.
Politicians' willingness to be grilled by broadcasters has always been about getting access to a large audience.
The thing to remember is that Ardern wasn't really speaking to Hosking during those awkward Newstalk ZB sessions, but rather to the 396,000 people who tune into the station every morning for the number one breakfast slot.
The question isn't whether it's democratically appropriate for her to ditch the show, but whether it's in her best political interests to do so.
Make no mistake, this was a carefully calculated media strategy decision, balancing up whether talking to Hosking every week was doing more harm than good.
In defending her position as the first Prime Minister in 30 years to cancel the weekly ZB slot, Ardern said the media environment had changed in that time and that there were now different ways to reach people.
This could be read as a reference to the increase in local media options, but it is also coming from the New Zealand politician with the biggest social media following.
So perhaps Ardern - who at any time can turn her phone into a propaganda machine - doesn't need Hosking.
Maybe the digital channels she uses give her better access to younger voters who might vote for her at the next election.
This sounds very similar to arguments made by major corporations, which in the last decade have switched marketing budgets from mainstream media channels and poured money into digital media.
Those experiments didn't go exactly to plan, with the marketing bosses at Adidas recently admitting they had over-invested in digital at the expense of their brand. Tech company Uber had a similarly stark wake-up call when the company realised it had spent US$100 million on online ads that weren't seen by humans.
Social media and its vanity metrics – likes, followers, comments – can be incredibly persuasive, but they function largely as a hall of mirrors, reinforcing what people want to see. The followers hanging on Ardern's videos and posts are among the converted. They don't need additional reasons to vote for her and her propaganda blasts aren't going to make much difference to them.
Political success is about asking swing voters to come over to your side, and you can't do that if you aren't talking to those swing voters.
It's been suggested there is no value in Ardern talking to Hosking's audience frequently because none of them would ever vote for her, but this is grossly inaccurate.
Ardern's unprecedented MMP victory in the last election is evidence that there are more swing voters in New Zealand than anyone realised – many of whom would have been tuning in to Hosking every day.
Ditching Hosking means ditching the opportunity to talk directly to the people who can pull an election one way or the other.
With all the emphasis placed on Hosking's interview style and worldview, one factor that's been overlooked is the level of trust he shares with that audience.
They listen to him, respect his opinion and often agree with his reasoning.
So when Hosking gives the Prime Minister a rating of seven out of 10 – as he did after her first 100 days in office – you can be guaranteed that many of that loyal audience will nod in agreement that she hasn't done such a bad job, after all.
When Hosking and the Prime Minister trade gifts over the Christmas period, this is simply another way he extends the olive branch from his centre-right to Ardern's centre-left.
Mike Hosking and Jacinda Ardern trading gifts. Photo / File
These moments may seem like soft non-events, but a compliment from your mortal enemy is infinitely more powerful than a few arbitrary social likes when it comes to nudging behaviour one way or the other. This is why politicians and companies are so hesitant to mention the names of their competitors in any of their communications – you don't even want to acknowledge the existence of the other side.
The problem with Ardern's ZB move isn't that she's going to disappear entirely, but rather that her silence will be filled with whatever pops into the mind of a slighted Mike Hosking.
And no matter what he says, the audience will be nodding over their Weet-Bix.
Newstalk ZB is owned the NZME Ltd, publisher of the Herald.
