They are cats.
That's fair, but I'm not fully convinced that the F-35 is so overmatching in a Canadian context. We have a lot of territory to cover, so we want planes that are able to handle rough runway conditions, rough weather, and have a long range. The F-35 is a bit of a princess, and I don't think its airframe compromises are as valuable in a Canadian defense context as they might be in an offensive context supporting the latest American adventurism abroad.
Having the ability to select lower-cost options that are Good Enough In The Context might be worth the higher cost of maintaining two supply lines. Plus, not every mission is going to need the F-35. Having to shoehorn the F-35 into every possible mission seems wasteful, if we can have a plane that costs half as much for the lighter missions, or twice as many of the cheaper plane.
I'd have figured that in a defensive engagement, land-based radars would provide a home-field advantage, so that stealth is not as useful as it would be on the offensive.
It's true that you don't want to be detected by an attacker either, but I believe that doesn't matter as much, since in an aerial engagement, the first one detected is the first one dead anyway.
So stealth is good, but not, like, as good over Canadian territory, as long as we're being supported by good detection.