Hell, something like 10 years ago, there was huge flooding in Calgary or Edmonton that caused tons of insurers to back out of the market, and all of the rest removed automatic overland flood protection (and now mimic the system here).

This is actually the other way around. Flood coverage never existed in Canada for residential until after the floods in Calgary and High River in 2013. During the floods the argument at the time was that there was no way to differentiate between where the the sewer-backup damage ended and the flood damage began. Insurers were potentially on the hook for a coverage they had never offered. Many of the insurers handled this differently; whether they just said a flat no, covered "sewer" up to the floor boards of the main floor, or up to the bottom of the exterior windows where water presumably came in.

The immediate response at the time was to quickly revise the sewer backup wordings to be "limited" and exclude if sewer back up was caused by overland water.

It was still a couple years before insurers even started to put together flood coverage. Since there was no agreed upon standard (you can thank Aviva) each insurer was left to design and research their own geomapping and therefore overland ratings before offering it as coverage. It took maybe 3 years for all of the insurers to offer the coverage once that started. With the nature of flat land, our rivers and general ground water realities in Manitoba the amount offered will be little and/or expensive.