Why does anyone pay any attention to the Preferred PM poll? It is meaningless. Yes, Mal is preferred PM at the moment but his party will be annihilated as things currently stand. And he's up against Bill for goodness sake. If they threw in Ray Martin or Nicole Kidman as possibles, they'd be preferred PM comfortably. It's a meaningless poll.
For the next election, Tony is the Libs only hope. He may not win but why would the Libs throw a new leader under a bus at the next election when it appears Labor will win 15 or 20 seats and hold Govt for at least 2 terms. May as well give it to Tony. At least he'll win back the base, which Mal has pushed away to One Nation, Corey Bernardi and "other." Winning elections is about winning particular seats, not being the preferred PM.