Earlier quoted context omitted.
Russians and Chinese are a major contributor, and they're not so affected by SV cycles.
I don't know about SV, but foreign investment is pretty dam low in Victoria, BC, which could be used as a proxy for Vancouver. 97.8% were domestic buyers.[1] It's not foreign buyers driving up the market in Vancouver, it's Canadians will to put themselves into serious debt in order to buy a house. [1] http://www.greaterfool.ca/2016/01/31/of-debt-data/
You get echo effects from places like Vancouver. Wealthy foreign buyers use high end real estate as a bank account increase the prices of top of the line housing significantly. Wealthier natives (Dentists?), now priced out of the highest end go down the scale and start purchasing lower end stuff with more money, increasing the price for everyone in a domino effect.
Government, not wanting the housing market to go down, create laws to allow subprime mortgage lending and buyers buy houses without real limits on price, and the middle class can now keep up with the price boom.