For whatever reason, Canadians seem to be more open to multifamily high-rise living. As a child in the 1970s it always seemed off to me when we'd visit relatives in smallish towns in Canada which had midrise buildings while in the southern US where we lived much larger cities had few recent buildings of similar heights. This is simply my recollection of things but it seemed like even a small town of 20,000 in Ontario had good odds of having a residential building at least ten stories tall. Perhaps it was a difference in government policy in how it built social housing?
Reduced heating costs perhaps? Heating from -40 to room temp is much, much more expensive than, say, air conditioning in the southern US. If you are not averse to sharing some walls, it makes sense.
Personally, I don't think I could go back to apartment living, but I will also readily admit that I am not a good candidate for "normal" in most regards.