I don't know what these 'curbs' are that you refer to, so I can't comment on that.
The housing shortage in Canada didn't happen overnight. This crisis has been decades in the making. Canada didn't have the same subprime mortgage crisis that you had in the US didn't happen here. And, while I won't say that NINJA loans were impossible to get here, mortgage regulations were/are more stringent here.
I read an article a few weeks ago that gave a very thorough explanation of how we got to this point. This one isn't bad, but not quite as comprehensive as the one I'm trying to find.
Between 1973 and 1994, Canada built 16,000 affordable homes a year. Why can’t we do that now? Our latest Hot, Hot Housing column.
thetyee.ca
The pandemic, during which construction practically ground to a halt and the following supply constraints provided the conditions where a problem turned into a crisis.
With labour and material shortages still a factor, developers have been concentrating on more profitable housing, rather than building for lower income families, leaving them literally out in the cold.