Lol, that's a horrible rule of thumb because you're saying that if my driveway was flat then I would have been on the right setup, which was running summer tires in two inches of snow.
Nobody is arguing whether snow tires are safer in snow but, depending on where people live, they are not necessarily a reasonable purchase. I haven't had anything but summer tires on my cars since 2012 and there is no reasonable need for me to swap. Tire choice, just like any other component, will depend a lot more on the users environment and experience than a simple blanket-statement regarding a small and ridiculously-short (for most people) section of pavement.
And tires don't just start breaking loose everywhere simply because it's colder. Traction is admittedly worse but, just like every other safety-related discussion, people seem to not want to realize that a person is driving. A car set up 'perfectly' can still be wrecked by an amateur whereas an imperfect setup can still be piloted safely by a professional. Just because you can't get there as fast doesn't mean you can't get there safely.