@lain Two reasons: one, the personal unpopularity of Justin Trudeau was apparently greater than I thought, so removing him actually did boost the Liberals (I hadn't expected it to), and two, Donald Trump's tariff campaign against Canada has soured Canadians on conservatives in general, despite significant differences between the Conservative Party of Canada and whatever Trump is.
I think the Cons could still win if they focused on culture issues, but now that's hard and not being attempted.