I can see the point from a supply-and-demand perspective. But on the other hand, isn't more densely populated areas more efficient, leading to less costs and le

I can see the point from a supply-and-demand perspective. But on the other hand, isn't more densely populated areas more efficient, leading to less costs and less prices in the long run? Is there simply not enough initiative for more dense developments, leading to the relatively few dense areas going up in price. Are the property costs the critical factor? I'm talking in general here, not about any specific city. Vancouver seems to have had a successful high-density residential zoning, but I've also heard that it's become very expensive... maybe because the greater Vancouver metro area is big (I don't know how it compares to the norm though).