That feels like a bit of a trick question - as big as I am on dedicated winter tires, I think a lot of people are sleeping on modern all weathers.

So, living in Alberta, and spending significant time in the AB/BC rockies in the winter, I still think all weathers would be feasible, but I'm more comfortable with dedicated winters. (For that matter, when I'm buying winters, I'm always borderline on whether I should get studded or not.) (And as a parallel effect, with dedicated winters I can also run higher performance all-season tires during the summer.)

And if I ran all-weathers with my driving patterns, I'd still want to be rotating them yearly, so that would cut my dealer visits by half, but definitely not to once every 4 years.

And tying back to my last ICE vehicle - for the first 4 years of its life it would have been okay without a dealer visit if you took tires/oil changes out of the equation, but not for any 4-year period after that. There are just too many random little things that break down in cars over time. (e.g. after 12 years or so the cruise control buttons were getting really mushy - I replaced them myself for the cost of the $65 part, but YMMV on whether you feel a service visit is warranted when removing your steering wheel air bag.)

Op is in a salt state (road salt, snowy winters). Dedicated snow tires are much better than all seasons to the degree I will take a 2wd Civic (with lsd) on snow tires over 4wd 4Runner on all seasons.

Also rotating tires every 10-20k miles is good because most cars run higher camber in the rear (inner shoulder wear) than front and the fronts wear the outside shoulder more because of turning. Swapping them extends tire life by spreading the wear.

The OP was asking about all weather tires which are rated for winter use in places like Quebec which require winter tires.

Not about all seasons, which are not rated for winter use.