in Canada, like in the US, it's a lack of supply mostly because of draconian zoning and land-use policies. Chinese immigrants are NOT the primary cause of housing cost inflation, and are likely not even in the top 10 causes.
The ALR bans any and all significant development in BC.
Land is not scarce in BC; land that it's legal to build on is.
Most of the land in BC is classified in this way.