The main reason Trudeau abandoned the attempt is that any method that would offer better representation for voters would ensure no more Liberal majorities with ~35% of the vote.

That's it. He had a majority in parliament. He could have rammed it through. Instead, he assigned his most junior minister to the portfolio and let it die in committee. Constrast it with buying the TMX pipeline, which happened lickety-split.

Winning the popular vote is vanishing rare in Canada, but curiously we've had a number of Liberal and Conservative majority governments with weak pluralities. Neither the LPC nor the CPC will change a system that benefits them, but if I were the NDP, I'd make common cause with the BQ and Greens and, if I won, I'd ram PR through on day two.