Doesn't even have to be a mansion. Some broke-ass bungalow is still worth keeping a death grip on unless if policies change significantly. Even if it burns down, the land alone will be worth a good million now, and will keep on rising.

Hold on to any property, even if you have to live in a tent on some barren soil until you can save up enough to have something half decent built.

Only real policy change can fix this, as no amount of money will be enough to fix this housing crisis. Even if the federal government puts in a trillion into new housing in Toronto alone, it won't fix this crisis until the laws themselves change.