The reality of car dependency there means that there are people driving and owning cars who can't really afford to do it properly, nor do they know they need to do it properly (e.g., having a second set of tires for the winter). You can see this evidenced by the rust buckets on the road that look like they are one pothole away from losing part of the vehicle body. Deferred maintenance and investment everywhere and in everything …
Also, you need studs or chains to get traction on ice. The difference between a winter tire and a summer tire is the temperature range where the rubber stays flexible. When the rubber gets hard, it will keep its shape instead of complying with the surface of the road, so it loses traction quicker. Ice is flat, so there's no difference between tire types, and there's nothing to grip on to.
The government has done ongoing research on these subjects and the regulations do get renewed (e.g. some properly rated all-seasons are now allowed)
Beyond the questions of winter weather properties, there are adjacent tradeoffs between the tire types (outside of studded):
1. Fuel economy
2. Noise
3. Degree of particulate pollution emission
I'm sure that the all-season tires probably have some negative tradeoffs in these regards to, which yields a choose the most optimal product for the time of year. All-season tires to me seem like a convenience food for places where the weather can be legitimately bad.
One other difference that is hard to articulate to North American drivers with respect to understanding Scandinavia and roads: there are places where snow and ice will literally not be removed (maybe not even removeable) from the road when plowed (I presume until spring melt). It just becomes a thick ice pack over the course of weeks. I never encountered any roads in my life (including Northern Minnesota) that were this inclement. North American roads tend to be cleared (plowing or melting) to asphalt or pavement.
If tires complying with the standards overlap, then the standards are meaningless. When there's requirements for snow tires, but not for X brand or model of snow tire, than it's not doing any good. That's why it's important to have a snow rating that can apply to tires of any type, and if it meets that rating, regardless of the rating for dry warm weather, than it should be good to go, otherwise not.
All seasons tires are rubbish. Also the "new" ones (re sister comment).
All-season tires have massively improved, but /so have summer and winter tires/. So sure, your all-seasons today may be superior to very old standards for prior generations of tires, but you are still the absolute safest when you have appropriate tires on your vehicle. Tires are fundamentally all that holds your vehicle to the ground.
Also as much as I love AWD, it does basically fuck-all to help in winter conditions. The thing you need to worry about is /stopping/ not necessarily getting going again, and in both cases a FWD car with winter tires is worlds better than any AWD car on all-seasons. I swap to winter tires on my AWD cars when I spend significant time in areas where it snows (e.g. when I lived for several years in Colorado). It doesn't matter how many wheels are used to drive, all vehicles use all 4 wheels to stop, but if you have no traction you are fucked. Anyone telling you otherwise is ill-informed.