My concern is that the opposition party is solely focused on Trudeau, and if the Liberals switch leaders, they may still be able to win the election. Mark Carney, is completely different animal. Or they may make things so untenable that the Cons can't right the ship in 3-4 years, and the Carney Liberals swoop in for another majority for 8-10 years.

The Cons are just Liberals that follow a speed limit. They still intend on moving in the same direction. It matters not who wins. "Progressive Conservatives" as the party name makes that pretty clear.