There's also just the unfiltered realpolitik long term strategy involved. If you know a government landslide is coming, then one perspective is that the best thing you could do for your party is try to use the landslide to remove the other opposition party. Then maybe in the next few years your party becomes the rallying point for opposition simply because there is no other.
Of course that failed in more ways than one.
Was the Liberal strategy really such a failure? The leader's personal defeat notwithstanding, the big story of the election was the Green party collapsing from 8 seats to 2 and now the Liberals are the official opposition with 3 seats. Presumably one of the three Liberals MLAs will become the new leader and by the next election the Liberals could be back in the game.
Yeah, but they didn't kill the Greens, which mean the opportunity was lost. Like both of the oppositions are battered and broken, but both are still standing with similar vote shares and seats. In that way, it doesn't matter who is LoTO cause the Greens and Liberal provincial vote bases are seemingly separate geographically. Extraordinary voter consolidation around either does not seem exceptionally likely in the near term, which means the Liberals failed. But who knows.