But remember that "always" here is relative to most of us being in our 20s and voting in the 2004 or later elections. In 93, and especially in 97 and 2000, the strength of Liberal majorities were significantly enhanced by vote-splitting between the PCs and Reform->CDA parties. Uniting the right gave the Conservatives a game theoretic advantage. That's an advantage that could be undone by uniting the center/left, and or if the Conservatives dissolve because of caucus tensions, and/or by pursuing electoral reform. Personally I'd rather see Canada adopt some measure of proportionality because I think there is value in terms of representativity and pluralism to have more than two parties, and because the false majority problem is a problem whether "my side" wins or not.
Edit: In 1997, there would have been a popular vote tie between Liberals and Reform+PCs, whereas the number of seats awarded was 155 versus 80. Even accounting for riding size inequality, most of that discrepancy comes from vote-splitting costing CDA/PCs seats they'd have otherwise had.
Here's a fun riding, look at 2000:
https://en.wikipedia.org/wiki/Leeds—Grenville
Liberal 18,594
Canadian Alliance 18,539
(55 votes between the two)
PC 7,940