Canada

They can build as many high-occupancy housing as they want. Just not in my backyard! /s

No, the number one cause is not building efficient high density transportation networks.

If you build efficient high density transportation networks like streetcars and subways, then people plan their lives around taking those forms of transportation, and thus will gravitate towards living near the stops and you naturally end up densifying housing around your network.

Endless suburban sprawl is caused by only building road networks so everyone plans their lives and housing around owning and using cars.

And at a fundamental level, corporations building out and then operating high density towers, is not building out a pleasant future to live in, it's building out a cyberpunk dystopia where the municipality expands vertically but cedes control of that expansion to exploitative corporations.

Canada has the existing space in our cities and towns and should be focused on turning more communities into Toronto's relatively dense 'streetcar suburbs', where you have a mix of lots of townhomes, semi-detached housing, and short apartment buildings, where people can for the most part actually fully own their property and building, while still supporting a relatively high density of housing. But we need to build out actual streetcar networks in cities other than Toronto for that to happen.

If you need apartments to solve this problem and not the fact that there is empty houses.... I gave up a long time ago but functionally speaking this encourages a wealth divide and is short term oriented

Do you have a reference for that?

My understanding was that developers stopped building "high occupancy buildings" in the 1980s/1990s when tax benefits for high density housing were removed, and condos became more lucrative. Since then, condos have gotten more expensive and smaller as investors take up more of the stock (owning ~40% of condos in large cities).

Of course, we aren't just facing a housing shortage we're also facing an affordability crisis due to a number of factors I listed in the post. I know that the Liberals and Conservatives have pushed the line that we just need to build, but I think that is mainly because they don't want to piss off older home owners (ie, the people who vote) by changing tax laws that would deprioritize home ownership as a retirement savings vehicle, and actively push down prices. The supply side is definitely a significant factor, but so are a number of demand factors.