You said, "Seems to me it's just an archaic left-over from days past."
Well certainly everyone that knows anything about North American history knows that Columbus certainly did not "discover" America at all. You know that right?
So why the pesistance with the false myth that Columbus discovered America? Why is it still taught in your schools? Why do they still have a 'Columbus Day?' One would think that L'anse aux meadows would have changed all that, yet it didn't even make a scratch on that venerable myth. Why is that?
In the same way, Canadians have their national myths - almost untouchable - about the Monarchy, all things British, General Brock, stiff upper lip and so on. Wink, wink; nudge, nudge, say no more. Why should we change all of this, when it serves us perfectly well? Why re-order government to satisfy something that, in the end, is simply esoterica that would get any ruling party tossed from government in a hurry?
When we talk about "costs" of maintaining such myths, well that is wholly immaterial since it serves peace, order and the greater good and all that rot.