This has not been my experience. Wife had Conti DWS on her C300 4Matic while I had General Altimax Arctic on my RWD 530i. Her C300 did very poorly in snow. My 530i did quite well.
Mine is actually the exact opposite with those tires; the DWS on the Evo did great while my current Altimax Arctics on the Focus are downright awful in the snow. Interestingly enough my roommate's old Saturn L200 with Sumitomo HTR A/S P02 felt more controllable than my focus on Altimax Arctics too. However the Goodyear UltraGrip Ice WRT were amazing on the focus so my conclusions could just very well be a tire thing. My GPS routed me down Utah route 62 and 22 from Capital Reef to Bryce Canyon in the winter of 2016-17 and only the northbound lane was partially plowed while the southbound lane (my lane) was untouched with ~6-8in of snow. The GYs were amazing when I had to switch back over into my lane because of incoming traffic.
I'm not well versed in Mercede's 4matic systems but the AWD system on my friend's 2014 E63S AMG felt very underwhelming compared to the Evo and STi. It was however a RWD system until slip was detected then it sent power up front versus the Evo and STi's always-50/50 torque split.
I agree 100% with you. Yes every area is different, but put here it’s hard to justify snow tires for the 5 times a year that you really need them because they haven’t plowed the roads. As I said in my other post, I’m impressed with the 3PMSF rated tires I just got, they even got over the ice dam at the end of my driveway with no issues.
I'm starting to believe this too. We only had 1 or 2 days since 2015 where there was more than an inch of snow that stuck on the road. The last one (minus this winter) that I can remember was 1 day in March around the winter of 2018-19 I think and everything was plowed by the time I got off work and melted within a few days so there's that.
The snow we received this week seemed to not faze many cars with A/S tires too - a lot of them looked more controllable than my car with snow tires.
If it wasn't for my winter road trips through Utah and Colorado I don't know if I would run winter tires anymore. A lot of people here rave about total cost of ownership but I wonder if they can say if having 2 days out of 5 years justifies the price of snow tires and when the local government takes care of the roads early in the day. With that said I'm more confident driving with snow tires than I am with all seasons so that does help.