Bruce Anderson sums things up regarding the poll here:
If the Liberals take two of the three byelections, they will have a bare majority, with the speaker potentially losing his job in favour of an opposition member to further cushion that majority. This scenario actually increases the chances of a fall election: Carney will want a formal mandate from voters with an appropriate translation in seats. Imagine the size of the majority that the Liberals could get in a fall election. Think Mulroney territory.
And if all of that wasn't enough to undermine the level of credibility that Pierre still has in caucus, there are rumblings that several more CPC MPs are going to jump ship post April 13th, using a different strategy: they will show their disapproval of Poilièvre's contuinued leadership by sitting as Independents, thereby sending a strong message to caucus that now is the time to dustoff the Reform Act and vacate the leadership, before Carney can move to an election, which could be held in November, right after the Quebec election. So, interesting times ahead with yours truly remaining skeptical that CPC MPs will really have the guts to put the Reform Act in play. I'll believe it when I see it, but the main point here is that Pierre's leadership becomes untenable right after those byelections. He should go then, but he won't. As for what happens after that, the decision largely rests with the CPC caucus. Leaders are supposed to put party first, but in the cold reality of political self-interest, they usually don't. Expect Pierre to be no different. Remember that, in the Quebec provincial context, Rodriguez's first instinct was to hold on. Unfortunately for him, his caucus had other ideas, and so he resigned in the end. In essence, that was the only realistic and honourable option open to him.