Regarding the "lowest # of housing units per capita in the G7", comparing Canada (median age of 41.8) to the 3 oldest countries in the world in Japan (median age of 48.6), Germany (47.8), and Italy (46.5) doesn't make a whole lot of sense given that kids don't buy or rent houses. Here's a slide from a presentation by BMO's Chief Economist which drives that home:
And France, which has by far the highest number of units per capita, and which has had basically stagnant population growth over the last decade, has seen property prices double in the last 10 years. There is clearly far, far more going on when basically the entire industrialized world with vast differences in population growth and immigration is all seeing huge increases in property prices.