they plow in illinois and they also do preventative measures to prevent ice buildup.
in wisconsin, madison they pretty much do nothing. its crazy slippery during the winter. but i think youre wrong about 4wd cars having trouble like 2wd if the snow is deep.... 4wd is a LOT better at it, because you arent dragging two dead feet through the snow.
anyone that says 2wd is fine either has active traction control or hasnt seen what 4wd does first hand (first foot i should say). and also, 4wd does brake better because youre engine braking all points of contact. it matters quite a bit, even with the small amount of engine braking that automatic trannys do.
My 300m did have traction control (the crappy kind where it applies the brakes when it detected wheelspin), that car was also heavy (around 4000 pounds), so maybe it had decent traction for FWD car. My 2 cars before that did not have traction control however.
Where I live now (and have for about 5 years) is about 20 miles from the Wisconsin border. We still get salt put on our roads in the winter, and they are generally plowed pretty quickly. Really, for my regular day to day stuff, AWD/4wd is only truly beneficial on those days when we get LOTS of snow. Like a couple of years ago when we got like 30 inches in a day.
Anyhow, AWD/4WD certainly does better at "not getting stuck", and, I imagine should be much better at towing in the snow, which is part of the reason why in 2010, I bought a Subaru. Though, I need to get a new trailer, and fix up my sleds to get them trail ready before I really do much towing in the snow.
That being said, I have family in Door County Wisconsin (grandma and uncle both in Sturgeon Bay area.) I've driven up in that area in winter for the last 15 years on icy roads (they get plowed, and then some sand gets dumped on em), never had an issue up there.