Ours is still the biggest decline. You're also missing the US which is a different story altogether... But even conceding that point, then compare to housing costs:

https://data.oecd.org/chart/6Ikm

And consider that housing costs for a desirable Canadian location (Vancouver, Toronto, Montreal, Ottawa) are much higher than that chart. And that the middle of nowhere in any of those European countries is still liveable whereas the middle of nowhere in Canada potentially means thousands of KMs away.

And that's not touching on other COL metrics where Canada is uniquely bad.