Housing affordability differs across Canada. In the map below, the housing affordability is being compared between Vancouver, BC and London, ON.
Affordability is measuring the house prices as well as income of different neighbourhoods in both cities. This is a better indicator that housing cost alone as it is total relative to the income people are receiving in the area, of whether it is affordable. For example, houses might be more expensive in Vancouver, than London, but the average income in Vancouver might be significantly higher which actually makes it more affordable in Vancouver than London.
The housing affordability ratings come from the 13th Annual Demographia International Housing Agency Survey: 2017 (http://www.demographia.com/dhi.pdf). This agency seems to be a impartial organization and therefore it’s data and affordable scale should be trusted (below image).
I think that affordability is definitely a good partial indicator of a city’s ‘livability’. Although I would not use this information on it’s own to decide whether a city is livable, it is a very important aspect. For example, although Vancouver is quite unaffordable, the benefits of living in a city that is close to mountains, the ocean, has lots of recreation available, and many things to do would make a city for livable for me.