Its too bad these videos don't go into detail on the actual snow depth, surface under the snow, air temperature, snow temperature, humidity, even snow grain structure. I'm sure Pirelli keeps track of those in great detail for their own testing.
My theory is that their are good cold weather -10C and lower tires(studless ice tires), and good warmer temperature winter tires(More open tread pattern, squared edge shoulders, often studdable), as none of the newer winter tires I've had, has done as well in deep, snow/slush or unplowed roads as the old style, open tread, very aggressive snow tires we used to have.
The new tires are better "overall" to the point that I just run them as all seasons, once they get down 6-7/32, but if you are bogging up and down hills on an unplowed logging road with 8" fresh snow, on 4" of loosely packed snow, around the freezing point, ice tires aren't working that well.
IIRC, the rubber classes of ice racing are running around 15-20 psi. Enough pressure to keep them on the rim in some ruts, and bumping and banging.