Its because they don't record the all too typical situation of a Canadian Citizen with financing via foreign relatives/friends.

Eg. Chinese family has one member whose been granted citizenship. They all come together to pool money, transfer it to the Canadian relative, purchase together, profit(for now).

All thats recorded is a Canadian purchased a home, "how" they purchased is not yet a government issue.

The government/banks/real estate industry has known about this for years...