We need to dig deeper to get to the bottom of this seismic shift. Here are several more convincing reasons why more and more Aussies are choosing to call New Zealand home.
It's safer for dogs. Extraordinarily enough, Mitchell Pearce isn't the first Aussie rugby league player to sexually molest someone else's dog: the pioneer in the field was Canberra Raider Joel Monaghan. As a dog owner myself, I can empathise with Australians who want to put 2000km of ocean between their pets and out of control ratbags who, like Pearce, "don't have a sexuality", which is a roundabout way of saying they'll have a go at anything that moves, especially if it's four-legged, furry and faithful.
You could even conclude that being an ocean away from Aussie rugby league players is safer for all concerned. The trail of havoc left by NRL players over the years suggests they model their behaviour on Alex and his Droogs in A Clockwork Orange, Stanley Kubrick's dystopian vision of near-future Britain.
One thinks of amateur proctologist John Hopoate who anally fingered three opponents in a single game. His defence was that he was trying to give them a wedgie but, as one of the rudely violated trio said: "I know the difference between a wedgie and someone sticking their finger up my bum."
And Anthony Watt, who ended up playing in the Gold Coast competition because no NRL club would have him. In 2013 he was suspended for eight weeks for biting an opponent's penis.
His defence was that he was wearing a mouthguard. He didn't say he wouldn't dream of doing such a thing; he said he couldn't have done it even if he had wanted to.
Climate change will make Australia uninhabitable. The Commonwealth Scientific and Industrial Research Organisation (CSIRO) has issued a series of increasingly dire warnings about what climate change will do to the land formerly known as the Lucky Country. Like the unfortunate British tourist in Ibiza, the Sunburnt Country risks being cooked to death.
CSIRO's 2015 update foresees temperatures rising by 5C and rainfall decreasing by 70 per cent by 2090, a devastated marine ecosystem and a marked increase in drought, bushfires, heat-related deaths and mosquito-borne disease.
The bad news is that Australia is going to become even more of a desert; the good news is that it has lots of feral camels.
New Zealand doesn't have to suck up to the United States (although it might choose to do so from time to time.) Lodged deep in the Australian psyche is the fear that one day Asiatic hordes (who obviously don't read CSIRO's reports) will sweep down from the east to seize Australia's mineral resources and secure lebensraum for their teeming populations. When teased about their paranoia, our neighbours tend to point out that we didn't have Japanese bombers over our cities and Japanese submarines in our harbours during World War II.
Thus the cornerstone of Australian diplomatic and military strategy is the American alliance, meaning American naval vessels are often tied up at Woolloomooloo wharf, not much more than a stone's throw from the Opera House and Sydney CBD.
While the US alliance has cross-party support, many Australians can relate to this Hopoate-inspired analysis of the relationship by former Labour leader Mark Latham who in 2005 reckoned then Prime Minister John Howard had "his tongue up [US President George W.] Bush's clacker that often the poor guy must think he's got an extra haemorrhoid."