Take where I live - Seattle - and the criticism makes a lot more sense. I live in a neighborhood about two blocks from a light rail stop and still walk by single family homes on relatively large plots on my walk from door to door. In nearly any direction, you are within a block or two of what one would say looks like a suburban single family home. There is the concept of "urban villages" which are small pockets of multi-family housing surrounded by low density housing.
I have a strong conviction that the reason Montreal housing is cheaper is in no small part because of the language barrier. Even if you could work remotely, why would you move somewhere you don't speak the primary language, surrounded by people that are somewhat hostile? It's a much smaller market.