[giallo]

There are a few factors at play here.
The first is the land issue. Vancouver and it's metro have very little available land to build on. Mountains to the north, the Pacific ocean to the west, and the US to the south.
The second reason are the ALRs( Agricultural Land Reserves). A lot of the remaining land in Metro Vancouver is farm land and cannot be developed.
Third is the cost of a single family home in Vancouver. The average price is around $1,000,000. You can get a two bedroom highrise downtown for a little more than half that. So first time buyers in Vancouver are drawn to highrises simply due to location and the relatively 'cheap' prices compared to a house.

As you can see it all comes down to the land crunch. Expect to see a lot more highrises and even a few skyscrapers in Vancouver's future.