It's not a housing shortage, it's a pricing issue.
If you do the math based on statscan data, there are FAR more bedrooms in Canada than people, even if you assumed couples never slept together and kids never shared a room.
People are splitting rooms to make it more affordable, not because rooms don't exist.
There are retired couples, or families with a single kid, living in 4-5 bedroom houses in Vancouver, because they either don't want to downsize, or they can afford the space so they buy more than they need.
The problem ais the distribution of housing, some people have too much, and some people don't have what we would reasonably consider enough.
There is also some distribution issues around where those houses are located compared to the desires of where people want to live. If someone has a house in Edmonton, but wants to live in Vancouver in a similar house and can't afford it, is that a housing shortage in Vancouver? I would argue it is not.
Where we define that "reasonable" line is where an ACTUAL shortage would come in. How much housing is reasonable for each person, and how reasonable is the location they want that much housing in?
However, I don't believe we have crossed that line. In my opinion we need to regulate the market better in order to have the distribution more aligned with overall social benefit. Of course we need to continue building more units with the population and to replace buildings over time, but policy could re-distribute the existing housing more fairly without needing a single one of those today.