I have nothing to back this up but didn't Calgary's big boom happen from 1995-2015 (ish)?
I don't think that era of community has aged very well at all. It's full of front-drive homes with no character and not much charm, plus the actual community designs prioritized maximizing those single-family homes and sprinkled in some strip malls to really depress you. I'm wondering as more new and better designed suburban communities are built, if homes from that 20-year time span will lose value and a lot of it.
My theory is even a updated/renovated home from that era is nowhere near as in-demand as a renovated home from the communities built pre-1990. Because at least those pre-1990 homes are closer to built-up amenities and city services. Meanwhile new and better designed communities can ride the wave of new home prices, plus they're new and better designed and not that much more inconvenient than homes built in that boom era. The 1995-2015 (ish) era mistakes will be very difficult to fix over time too; the main streets program surely will not help them become more livable.
In the years ahead as people who bought those homes when they were new, raised their kids, and are now looking to downsize and put the house on the market, maybe we will see Calgary's price drop. Granted demand for pre-1990 could push prices up and people moving to Calgary could also offset any losses in value seen from home of the 1995-2000 (ish) era.
Calgary and Edmonton are both getting increasingly dragged down by the communities you mentioned, but I would extended to say most 1970 - 2000 communities is where our biggest problem is. We have like 50% of the city's land area in a "declining" ring where populations continue to drop, buildings continue to age and redevelopment is unlikely to come very quickly to all these areas as the supply is so huge. This area has seen enormous population decline as the average number of people per house continued to drop.
The central issue is these areas were mostly built single-use residential at extremely low intensities, with limited obvious redevelopment. It's a non-resilient design and it's proving out in real estate markets.
If your neighbourhood was built for 10,000 people in 1970 but only 5,000 people live there today - likely your shops are schools are closing from ever-lower demand. This triggers the negative feedback cycle - lower quality amenities, and outdated housing stock makes the area less likely to attract attention from either gentrifying or redevelopment forces. Stagnation and decline is the path these areas are on.
So you are a stagnating and declining neighbourhood, what now? I see these 1970s - 2000 communities having three options:
- Renovate - fix up the housing ad-hoc, as each owner decides what to remodel and when. This will keep some of the housing stock competitive with brand new housing elsewhere and is relatively cheap. There may be specific attractors that help some areas retain popularity better than others (@MichaelS cul-de-sac example). This doesn't solve the bigger picture - renovations alone are not likely won't create enough growth to re-open a school, but may attract enough to keep one from closing - it "soft-lands" a community into a lower intensity for medium-term stability.
- Gentrify - try to become the "next Mount Royal". Large land plots where the high cost of maintenance is compensated for by increasingly attract wealthy, single-family home owners. This is the market for 1-to-1 redevelopment beyond just piece meal renovations - 1 small, obsolete house is replaced with 1 large, expensive house redevelopment. Gaps in local services that exist due to lack of population are somewhat compensated for by much higher local spending (e.g. 1 rich household buys dinners out 5 times a week, offsetting 7 middle-income households that used to only go out for dinner once a week).
- Redevelop & densify - start replacing obsolete housing with newer, more competitive and more diverse housing types so the market demand your neighbourhood caters to is getting bigger and wider. This is the process well underway in the pre-1970 areas of the city. Replace large, obsolete homes with a duplex or some townhomes. Add an apartment block here and there. Build back up the local population enough that retail is starting to be attracted, new clusters of jobs and activities form and new main streets develop. This triggers a positive feedback loop - greater amenities and options supported by greater populations, makes the area more attractive for yet more people and more amenities.
All these options take money and overall population growth - as long as both continue, the paths are open. However, the only long-term solution is the redevelop and intensify option - resilient, sustainable communities need more housing diversity and higher density that simply wasn't built into most of our 1970s - 2000 era communities. Through diversity of housing options and price points at a sufficiently high intensity, communities are far more likely to be resilient to future economic changes and continually be able to re-invent themselves, while maintaining their attractive services and amenities.
Demand is limited though - not everywhere is in enough demand to be redeveloped, not enough rich people exist to gentrify every community, not all homeowners can afford renovations. The result is you'll see a wide spectrum of 1970s-2000s community outcomes and some seem likely to continue to stagnate and decline.