The wider range of voices in the upper houses is due to multi-member electorates, not preferential voting per se. Australia's hung parliaments are historical a

The wider range of voices in the upper houses is due to multi-member electorates, not preferential voting per se. Australia's hung parliaments are historical aberrations; I expect that the historical pattern of clear lower house majorities to resume over time. The economics of bloc formation and ordinary logistics create constant pressure on any party. It's possible that Labor will be replaced by the Greens, or that they will form a permanent coalition like the Liberals/National/LNP/CLP chimera. But that will still be a de facto 2-party system.