I think so. It's quite likely we're already over 1.7M. Not sure if the Foothills district will be added to the CMA by the next federal census but if it does, that would make it pretty close to 1.8M today.
I consider Foothills part of the CMA. Even if you add Foothills, Calgarys metro area would be between 3000 and 4000 Sq mi which is way smaller than pretty much every 1 million+ metro area in the US. Many US metro include areas that are well outside their commutersheds. Controversial opinion: Calgary is bigger than Columbus, Nashville, Charlotte and Kansas City IMO (among others). Maybe not officially, but when you consider a proper definition of the number of people within what can be considered an urban area.
US metro areas are defined entirely by their commuter sheds.
The US Census Bureau definitely defines metro areas at much larger scales than Statistics Canada. Case in point: metro Chicago is 28000 km2 (holding just over 9 million people). Metro Toronto, on the other hand, is only 6000 km2 and holds 6 million people. The "Greater Golden Horseshoe" is closer to metro Chicago's size (30000 km2) and includes cities like Hamilton, Barrie, Kitchener-Waterloo, etc. It is almost 10 million people. So, Toronto really is slightly larger than Chicago, but the different definitions of "metro" make it seem like Chicago is much larger.
Similarly, at 1.4 million people, metro Calgary looks similar to metro Oklahoma City, but it's less than a third the area (5000 vs 16000 km2).
CMA (and the US equivalent) CBSA aren't just based on vibes or whatever, they're based on commuting flows. The Canadian rule is that an area needs to have 50% of their workers commuting into the centre to be counted as part of the CMA, and that they don't allow holes, so Foothills can't join independently, the combination of Foothills and the other communities within it (Okotoks, High River, Diamond Valley, Longview) have to qualify. And they haven't; they've gotten further away from that 50%. They were incredibly close in 2011, and have drifted away as Okotoks and High River have become larger and more self-sufficient, and then in 2021 with the spike in work from home. And because Foothills has started to try and grow jobs in the Aldersyde area, I'm not sure that it's likely in the next few decades either. The figure below shows the trend (Foothills combined is the grouping I mentioned above including Okotoks, High River, etc.; similar for Rocky View combined including Airdrie and friends.)
(Note: The above is me explaining what the StatsCan policy is, not defending it; to me it's pretty intuitively obvious that Okotoks and Foothills belong in the CMA.)
The reason that CBSAs in the US are larger than CMAs is due to three things:
1). Longer commutes overall and more dispersed exurban populations.
2). Use of 25% commuting flow, rather than 50% commuting flow in the definition.
3). Use of counties rather than municipalities.
The third one in theory is neutral, since a larger county can be excluded as easily as included, but I suspect it tends to make the metro areas larger.
The 25% commuting flow would make a big difference in Calgary; Foothills would be in, as would Wheatland County including Strathmore. But on the other hand, they wouldn't add that much population; to the 2021 population of 1482K, they would add about 75K and 25K respectively we'd be 7% bigger, which is something, but isn't that big a deal. It would increase our area from ~5087 to ~13200 sq km, but I don't know anyone serious about urban areas who thinks of the physical land area as being particularly meaningful.
And as far as Toronto goes, I had a look; using census divisions (the subdivisions that Statscan uses are too fiddly), and using the US 25% commute definition, the Toronto CBSA would build on a core that included York (Richmond Hill, Vaughan, Markham), Peel (Mississagua, Brampton), Halton (Oakville. Burlington) and Durham (Pickering, Oshawa). With that core, the only census divisions that even have 25% commute flow to add to that are Dufferin (Orangeville, Shelburne) and Kawartha Lakes. So the Toronto CBSA winds up going from 6,202K and 5902 sq km, up to 6,858K and 11644 sq km; about 10% more people.
The US Census Bureau includes a second definition (Combined Statistical Area) that uses a 15% commute flow and does a two-way interchange calculation that I'm not going to bore anyone here with. It defines some much larger metro areas; some that might not be that surprising (San Francisco-Oakland-San Jose; Salt Lake City-Provo-Ogden; Raleigh-Durham-Chapel Hill) and some that might (Boston-Providence; Washington-Baltimore). Using that definition and census divisions, the greater Toronto CSA would expand substantially; it would include Hamilton, Barrie and Guelph, along with Peterborough and Cobourg-Port Hope. It would have 8,438K population and 25,934 sq km. The comparable definition of Chicago would be 9,987K population.
The other cities in southern Ontario are sufficiently self-contained that they wouldn't join this new conurbation. There is really not that much long distance commuting.
