Is it really so impossible?
Our political duopoly is less than 100 years old. The Liberals were a party of government within living memory. In a situation where there is general disgust with the political caste and no enthusiasm for either of the two main parties or their leaders why shouldn't a third party sneak in and carry off the prize? The only thing that stands in the way of this outcome is a weary fatalism that negates the possibility of change.