You have this wrong.
Vancouver and Toronto's house prices are partially if not wholly supported by foreign buyers, who are buying both detached homes and condo units. You mention that the goal is to make detached prices expensive but non-detached prices stable and affordable? In both Vancouver and Toronto non-detached prices are not stable nor are they affordable - look at the condo market in Toronto, which continues to be on a tear despite the downturn in detached housing prices.
Vancouver and Toronto are far from what we want - certainly they are denser cities, but the current boom is stretching wallets for most of the citizens of those cities and making them unaffordable.
We need well designed, well-planned urban development. We don't need policies to change tastes through making things unaffordable. Instead, we need policies to encourage effective and tasteful public spaces, easy access to transit, and walkable neighbourhoods with work, housing, and retail.