Turnbull has been between a rock and a hard place for the entire time he's been PM and, even with a bewilderingly bizarre upper house poking holes in his legislation, delivered results. Australia is doing well. Its economy is doing well.
Shorten, one of the most feared men in the union movement (though appearing to resemble a piece of wet lettuce in TV interviews) is undergoing the most intensive media training in history. The zingers are gone, he doesn't look like a Thunderbirds puppet (so much) and is approximating normality on camera rather than exhibiting the previous homicidal rage in his responses to journalists he has a history with.
On Turnbull's other side you see Eric Abetz, the Tas "Liberal" religious conservative powerbroker responsible for losing three lower house seats and an upper house seat in the 2016 election, is still on a Godzilla rampage. So is Abbott. So is Cory Bernardi, the other part of the Democratic Labour Party (AKA National Civic Council) Catholic extremist infiltrators of the Liberal Party. (Yes, I know, most Catholics are cool. I was one. But we're talking about the nutjobs.)
Menzies would kick the religious extremists out in a heartbeat. And win the next election in a landslide.