Jobs are generally the driving force for growth, but for international immigration it's not always job related. We'll see Calgary's population growth start to slow (as it will for the other major metros) as international immigration slows, but lack of rent control or cold winters or good transit won't factor in much. Even with lack of rent control, rents are still cheaper here than 5 of the other 6 metros. Outside of Vancouver's winters, the other 5 metro's winters aren't drastically different enough to make a difference. Transit is lacking compared to the big three, but I rarely meet people from other cities who make their decision based on transit.
Calgary is in enough of a sweet spot, that even though it will lose out in some categories, it usually does well in others. For example.
- Calgary transit lacks compared to the big three, but it's here easier to afford a home that's not far from downtown. It's also easier to drive here, and many people still prefer that mode.
- Calgary is colder on average than Vancouver or Toronto, but gets more sunny days. Calgary beats out Ottawa and Edmonton for Winter weather.
- Calgary accommodation is more expensive than Edmonton, but still cheaper than the other metros. Similar cost compared to Montreal, but higher wages.
I'm not trying to say Calgary is better than those other cities, only that you can't really look at population growth as being determined by public transit or cold winters, and that it's no harder to live here than it is anywhere else without regular employment.