It might be better to look at the US as an outlier here. Those Canadian salaries (esp if they're slightly low based on the other comments here) don't see too dissimilar to what's available in the UK (outside London which has higher salaries for every job due to cost of living).

At the end of the day, those 'low' salaries are only low relatively. They are more than enough for most people and only a reason to move south if your main driver is money. Otherwise they're good enough.