So what - there are probably still a few thousand house-rich old Vancouver/Toronto people.  The federal tax people need to cross-check the property sales with their income tax information - and of course there will be no sale in the case of your 1970 purchasers, who still live in their house.  And they will be retired.  And the CRA can instantly see the couple's  age, past income history, etc., see they are collecting CPP/OAS, and not working any more.  There is no "non-reporting of income" issue.  So while you are technically right - such people are part of the explanation for the crazy ratio - we should still crack down on all the blatant tax liars.