No. The winner takes all nature of each seat does tend to lock out candidates who might get in with proportional representation with multiple candidates per se

No. The winner takes all nature of each seat does tend to lock out candidates who might get in with proportional representation with multiple candidates per seat, so it encourages dominance in that regard. One could say that this is a weakness in the Australian system. Maybe there should be one big electorate with 151 candidates elected on a proportional basis? The main benefit of the preferential system is that it allows people to safely take the risk of voting for a third candidate. I see it as question of incentives more than raw maths. (Everything I'm saying is from the perspective of the lived experience of being under a RCV system, not the raw maths.) By way of information the upper house does use proportional representation with typically 6 candidates chosen from each state, each state being a single electorate. Smaller parties do regularly win a number of spots in the upper house.