I think the true cause of the unaffordable housing is the insanely low interest rates. The people at the helm are attempting growth at all costs.
Edit: it is really interesting to contrast Toronto with SF. Both are really nice places to live without cost of living concerns. Both have insane home prices. Rents are relatively cheap in Toronto because of basic demand and supply. SF has great paying jobs, Toronto does not. Will be interesting to see how things pan out over the next decade in both cities.