Two other data points, Canadians have a wealthier middle class, and as a whole are much wealthier than Americans. So maybe the prices are just reflecting that Canadians can and will pay more for places?
You can get some truly cheap housing in the US. My brother rents an apartment that's probably 800 sq ft two bedroom. He has a roomate, they each pay $250 a month. It's in a nice city, and the building is in nice shape.
I wonder if anyone's living in Buffalo and commuting into Toronto each day? Making Canadian money and paying Buffalo prices, the new wealthy... I guess the same could be true for BC as well.
There are less expensive places in Canada too. Rural areas, smaller cities (Windsor, etc.)
Also, keep in mind that the figures I linked are for family income (generally 2 earners). It'll be a bit higher in the big cities.
In addition, many big cities follow policies that tend to boost prices. Zoning restrictions, anti-sprawl legislation. The feds help boost prices on the insurance side via the CMHC. Etc.
All that said, young families generally have a hard time buying - even with the low rates - without help from family.
The real estate market seems quite stretched to me. It's got to the point where you could buy a house in a big centre, or opt for one in a smaller town (or the U.S.) and enjoy a modest retirement based on the price difference.