The fundamentals have never supported the rapid price appreciation and RE frenzy we've seen in the GTA. It's one of the biggest RE bubbles in history, and Canadians currently carry more household debt than any other G7 nation (over 2 trillion dollars worth, of which mortgages are a whopping 65%).
On another level, this is likely an orchestrated wealth swindle on par with the financial crisis of 2008. I've never seen so much debt stacked on top of leverage stacked on top of more leverage. All of which must be paid back, eventually, somehow. It's all very precarious and risky. Lots of folks might end up being pounded back to the financial stone age (and watch for the hat to be passed for "bailouts").
Interest rates will eventually rise. And despite the lows, many people are strapped right now.
I somehow doubt that many of the newcomers to our city arrive flush with enough cash to buy our housing stock, much of which in any other North American city would be considered complete crap. Despite our "schools" and "weather" and "safety" and "stability", there is not enough intrinsic value in these asbestos-laden, pest-infested tear-downs to even come close to justifying the prices.
Also, the rapid population growth may have abated, according to a recent Macleans article:
Basically, it's NEVER "different this time". All things being equal, there is nothing at all to justify this housing market other than the usual suspects in any asset bubble: fear and greed.