Geographically constrained in 3 directions.
Only decent-weather locale for Canadians (US has hundreds of release valves for people that get sick of prices in SF / NYC / etc.)
Large rich Chinese immigration.
I would argue the latter 2 arguments have some bearing, but imo it's more about cheap capital coming in from many directions including locally for so long in combination with artificially choked and inflated development processes for decades. For example, there's a parking lot with an old grocery store sitting there at the busiest transit hub in the U.S and Canada. The proposal to redevelop the site has been repeatedly stalled every year for what is now 6-7 years, meanwhile only the most meager development projects have gone forward in the same neighborhood. That said, because of the other reasons, as soon as it hypothetically went up, all of the units would be purchased by speculators because they'd be wildly out of reach for any regular person anyway, due to decades of the other crap.
I went to an open house yesterday for a modest one bedroom with no interesting view or extravagant features, listed at $750k. When I remarked that the cost of the mortgage alone would be a multiple of 2.5 - 3x our current all-in expenses, he simply suggested that in 5 years I can just move out and hang on to it, renting it out to someone and keeping another unit off the market.
The geography is a constraint, the problem is failure to embrace the constraint in any sensible way. Prairie cities would be more economically productive and less horrible in my opinion if they halted outward expansion decades ago and just figured out how to adapt correctly.
Regarding east van where I live now, I went to an open house yesterday on commercial drive that was 1 bedroom for $750k facing west and looking at buildings that have been there at 1 story since maybe the 50s.
The gap is just so enormous, considering we rent a studio basement down the street for $1500 total.
Our 1000 sqft house in the West End was almost 300k in the mid-80s and our family was struggling financially but we were in the best school district so my parents made the sacrifice. It was almost double the price of a much larger house in suburbs of Toronto.
East Van was cheaper but still expensive relative to other cities. Vancouver house prices has always been a mystery because there is no inherent industry to pay for it. Locals blamed Asians but Germans were larger demographic in terms of immigrants but you couldn’t identify them as easily.