“Statistics Canada says that trend is being driven largely by the province of Quebec, where 43 per cent of couples live common-law. Remove Quebec from the equation and the percentage of couples in Canada living common law drops to 17 per cent in 2021.”

This is probably (still) a reaction to decades of dominance by the Catholic Church in Quebec. The only reason the percentage isn’t higher is that some activities outside of Quebec have problems if a couple is not married (emergency health treatment for example). And I didn’t think Quebec follows common law?