Australia doesn't have a presidential political system. We also have compulsory voting unlike the USA, UK and most European nations which makes it harder for third parties and independents to win seats in the House of Reps where our government is formed.
Australia is not Europe nor America despite what the cultural cringers think
. Our demographics are different as well. The economic centre of the world is shifting towards east Asia and the Pacific. Bad news for old trans-Atlantic countries (Western Europe & Eastern USA) which have dominated world trade and power for the past 300-400 years, but good news for Australia as we are geographically in the region and will no longer be at "the arse end of the world".
Also traditional ALP voters, with the LNP in government, would not vote for another Conservative party. In any case, any disaffected working class voters would more likely switch further left to the Greens, to the far-right (One Nation) or to a high profile populist candidate (eg: Palmer, Xenophon, Hinch, etc.). Bernardi has no profile outside of SA and Andrew Bolt blog types. All Bernardi will do is split the core LNP base in SA and other parts of the country his new party challenges in. That only benefits the ALP. The current LNP government is a disintegrating rabble at war within itself. What will be interesting is whether Christensen, Abetz, Andrews & co. will follow Bernardi. If this really gets ugly then it could bring down the government and send us to the polls again sometime this year.