Agreed, but the NDP and Greens were PR or bust while the Tories figure moving to such system would tear their party apart as they can appeal to 40% by being moderate enough to appeal to swing voters while right wing enough to keep their base happy.  They cannot appeal to 50% while simultaneously keeping their base happy.  Now perhaps ranked ballots would lead to another split the moderate party of the split might win on second choices, but certainly the Conservatives in their current form couldn't.