I think you are incorrect. Watch this video. The all seasons actually brake better in dry and cold conditions than the winters. I have seen several tire tests in dry/cold conditions like this and the all seasons win out in braking every time. In actual snow/ice, the winters do better, but the soft compound winters don't do you any favors on dry pavement. I have dedicated winter rims/tires for all 3 vehicles here in Calgary.
I think there is no doubt A/S. tires greatly improved. However, doing better in dry conditions in cold usually means sacrificing performance in other conditions, snow, ice, slush, freezing rain etc. I personally keep A/S on BMW until ski season seriously kicks in bcs. have two other vehicles on snows. Michelin Pilot A/S 3+ I have on Tiguan is serious tire in summer and keeps good performance in cold. I had DWS before on the same vehicle, and in cold they were really, really good (not as good in dry like A/S 3+). So, yeah, A/S/ tires are getting better, but....