the Canadian pendulum was due to swing back to the Cons

Sure, for the opposition leader it's a matter of adding or removing momentum to the pendulum swing. He definitely added a lot of momentum, to the point that the Liberals had to throw the PM and its climate policy under the bus to get one more term. That's a hell of an effective opposition leader.

Any influence gained was because it was “their turn”, not Poilievre’s leadership.

I'm not saying that he's a genius or anything, but making good use of your "turn" is not an easy task. He has demonstrated that he's good at it, to the point of landslide victory projections 6 months ago.

would have won if it wasn’t for Trump slapping Canada in the face

And that's exactly why it's going to be easy to brush off his loss. Sure, he'll face criticism on his failure to pivot the party messaging post-Trudeau, but that was a nearly impossible situation. Would any other CPC MP have done a better job of riling up the conservatives against the Liberals without in the end get blindsided by anti-republican sentiments? Jamil Jivani? I don't see any reason to believe the CPC will have a better shot with someone else.

If they do end up booting Poilievre out of the leader seat, it will be because the CPC is a bucket of selfish snakes and lizards vying for power. It is possible. Surely someone is salivating at this opportunity. I just find it unlikely, because the vast majority of MPs are satisfied with his work and will simply bide their time, they'll be better prepared in two years.