If they fill up because they're cheap, that indicates market demand that will bring the investors back. You're not going to keep them out unless Vancouver becomes, in significant part, a ghost town.

Which has another cost: everyone here who owns their own property would see their most significant asset disappear as the value of their home plummeted along with all the investment properties.

If I could do the same for food, we'd soon live in a hellscape of rotten food.