It's zoning which forbids the construction of any denser forms of housing than single-family detached houses in the vast majority (like, ~90%) of the land in most Canadian cities. And more broadly an insane amount of bureaucracy and friction that developers have to go through in order to get a building approved. In Vancouver, they are literally tearing down apartment buildings and replacing them with multi-million dollar mansions, within walking distance to downtown, because it's no longer permitted to build apartments in the neighbourhood and the buildings are end-of-life. Check this map here, all the yellow areas are zoned for houses (luxury mansions in this market) only https://maps.vancouver.ca/zoning/.

This (https://www.google.com/maps/@49.2632824,-123.0709435,3a,82.3...) is across the street from Commercial-Broadway station, the busiest skytrain station in Metro Vancouver at the intersection of the two major lines. The lines were constructed in 1986 and 2002 so they've had a good 37 years to densify the area. It's the same story in every city outside of Montreal and Quebec City.

Then there's the many ways that Canadian homeowners benefit at the expense of everyone else from subsidies. Unlike in the US, capital gains on primary residences in Canada are completely tax free with no limit. That incentivizes people to invest as much as possible into buying as much home as they can. Then, in some jurisdictions like Ontario and BC, owner-occupied homes are actually charged less property taxes. In other words, renters are subsidizing homeowners. Then, in some provinces like in BC, you can actually apply to defer paying property taxes entirely until you're dead at which point the estate pays the balance. Further, homeowners with a home worth less than about 2.125 million, and you are 65 or older, you are eligible for a grant of $1045 per month discount on your property taxes simply for being a poor downtrodden homeowner. Being a homeowner also gives you the right to vote in every municipality that you own property in. So we have a municipal politics in which property owners are given more of a voice than residents themselves. Absolutely fucking disgusting