Essential Poll Labor 52% Coalition 48%, page-82

No the difference between winning and losing at the last election was the fact that Mal had a 15 seat buffer. And he needed all but 1 of those seats to hold on. The point about bringing Tony was this:

The Libs will be slaughtered at the next election if Mal is leader.
He should be replaced to avoid the slaughter but the Libs will, more than likely, still lose. And there is no ready made leader in waiting in the Libs, Tony aside.
Why put a new, untried leader in now, to get belted at the election and face two or three terms of opposition?
Put Tony in. He will probably lose but not as badly as Mal will because Tony will recapture the Lib voters who despise Mal and who have turned to minor parties. He'll reclaim the base and in the right seats. And Tony is saying all the right things, all the populist things (if you're a Conservative). There's almost an element of Trump about him. He's rolling the dice on people's resentment to political correctness and Conservative's resentment to Mal. And there is plenty of that but you won't hear about it on the ABC or Fairfax. Assuming he loses, he'll gracefully retire from Parliament (and Justis will have nothing to post about!!).

The TPP polls are where they were when Tony was replaced. So much for Mal's popularity. It really has worked wonders for the Libs. And the longer he holds on, the more people will tire of him, particularly Lib voters. He still might get that primary down to 31-32%, if he gets the chance.