The 10 year multi-entry visitors visa has become a de facto residency program coincidentally timed with the runup in price and demand in both Vancouver and Toronto. Over a million of these visas have been issued to one country alone - China.
You can live here, buy as many houses as you like, send your kids to school, avail yourself of all community amenities, and bonus, you do not have to report or pay tax on your overseas income.
Add in local speculators and  ramped up immigration programs, student visas, TFWs, provincial nominees, investor immigrant programs, and the sky is the limit for demand for our homes.