A lot of good things happened for the CPC under PP (unfortunately for the rest of us). Trudeau had to step down, the carbon tax is gone, the CPC gained seats and secured a record number of votes and the "far left" has been wrecked. While the liberal narrative is that PP fumbled a huge lead, I think cons see it more as carney resetting all the work PP did to discredit Trudeau, as trump interfering with the election (for his own gain, they think Carney is weak and will fold to trump) and they see the polls tightening as the election got closer (and him out preforming them) as a sign of PP's success. They think Carney will show his true colours soon enough and become as unpopular as Trudeau, allowing PP to win.

O'toole didn't acomplish much of anything during his time, the CPC mainly stayed the same or slightly declined despite liberals being steeped in controversy.

Sheer one his leadership race by a very small margin while the CPC (and right wing politics in general) was having an identity crisis, while they gained ground under him they did not make the strides they expected. Sheer also had that financial scandal.

I think PPs perceived performance is much closer to Harpers first loss. but even that isn't a great comparison IMO we are in new territory, exciting times and all that.

Disclaimer: I voted green, when I talk about good or bad here I'm putting myself in the shoes of a conservative voter, and I'm talking about perception as the right wing sees it, not necessarily fact. Their feelings don't care about your facts :D