This is not how housing works. We're talking about the housing crisis, and the human right to housing is about those who need it the most. For any new housing that's built, whether it's a rental or single detached home, mortgages will cost more than for something that's already built. New constructions, unless they come with subsidies, will not create the affordability needed.
The market needs to be regulated. In Canada, we have a market-driven economy, and it's the role of government to put protections in place to protect people from harm. It's the same way for minimum wage in this country. The market will not address that in itself out of its benevolence, especially when we have financialized actors who are beholden to their shareholders and people get bonuses when they get maximum profit.