My experience of riding in winter is that ice isn't the problem if you have studded tires. Snow is.
I have never ridden a regular 622-40 stud-tired bike in icy conditions where riding would be dangerous (so presumably studded tires on a fatbike will work perfectly in all ice conditions too). However, when stopping at traffic lights, when you have to put a foot down, that's where the danger starts and you have to be careful not to crash when stopped. The tires I used were Nokian / Suomi Tyres (former name / current name) W240. Perhaps some tires with studs only in the middle might be dangerous in some icy conditions; W240 has four lines of studs and when using it, I never encountered any dangerous icy condition.
However, snow is a problem. A very big problem.
Firstly, you notice that fresh snowfall can be ridden through, but once pedestrians have made the snow layer uneven before it has been plowed, riding is very annoying. A fatbike might make it less annoying since you can reasonably run reduced pressures.
Also when roads aren't plowed often enough, they might develop a thick layer of hard snow. When the spring arrives, and snow melts, that thick layer of hard snow becomes a thick layer of soft slush-like snow. Riding through that is practically impossible and very dangerous. So even if roads are 99% free from snow, the remaining 1% slush-like snow can be a genuine hazard and you might want to dismount and walk. If roads are plowed often enough, this problem doesn't happen, but then again you can't rely on all roads being plowed often enough -- even one minor part of road where plowing was skipped during a snowstorm can eventually become a genuine hazard during the following spring.
Fatbike with studded tires solves all ice problems and many snow problems but not all of the snow problems. There are still environments that have snow and can't be ridden through with a fatbike.
The voice in this video is Finnish but this video even for non-Finnish speakers demonstrates that fatbike doesn't solve all snow problems (and that it's a bad idea to use non-studded tires on fatbikes during winter):
I'm sorry but a bike is not a car. If public transportation is not an option, in areas that have winter car is mandatory (or you could use a taxi during the worst days...). You might want to ride bike often though instead of a car, even during winter; in many winter weathers including snowstorms, fatbikes work well. But there are road conditions where a bike just won't work. Especially if bike paths are segregated and plowed less often. Well-plowed paths are safe.