The statement that "the NDP and Green Party aren't a political threat to the Liberal party" is a staggering misunderstanding of a situation on which you are speaking authoritatively.
With the utmost respect, I think an elementary understanding of multi-party democracies would be a useful first step for this discussion.
It may be instructive to look at some of the key Canadian swing ridings:
There's a reason that Canadian Conservatives have fought tooth-and-nail against any type of ranked-choice voting system. I genuinely believe that the Conservatives would not win another election in my lifetime in a ranked-choice system.