The F-35 always seemed like a funny choice for a mainline fighter for Canada. Even the US has invested in many more F-15EXs. Having a Hi/Lo mix makes sense for a larger force, but equipping a smaller force with only exquisite birds doesn't seem to make much sense.

Then again, this is Canada - sensible decision making in military procurement just isn't something that happens here.

But the economies of scale are such that at least the $$ isn't completely out of whack (for purchase at least, maintenance I'm not so sure of). I would wager that the cost of maintaining those ancient CF-18s is pretty high now too though.

The F-15EX is designed to be a stand-off missile truck that works in tandem with a network of forward-deployed stealth jets. This compensates for the relatively low ordnance load-out of stealth jets. A stealth jet can designate and cue a target from the front using an F-15EX as a missile launcher safely in the back since it is non-stealthy.

The F-15EX isn't a particularly survivable aircraft on its own. It is a plane you'd only use if you have stealth jets and you plan to do air combat at scale. It augments the capabilities of something like an F-35 but isn't something you'd add to your fleet unless you had a lot of stealth aircraft.