In 16 years of driving a 4wd truck with mostly very light at or all season tires, I've pulled over 30 cars out of a snow bank or ditch and maybe 4 or 5 of those cars had snow tires and at least 1 had studded snows. I've never gotten stuck and never hit anything. I've been 10 miles up dirt road/4wd trail and had it snow 3 feet in a week of elk hunting and drove right out with snow up to the tops of my tires. I have chains for the truck and have only used them once to pull a 30 foot class A RV 2 miles up a dirt road from an elk camp when it snowed 2 feet on us. It was a steep climb so the chains came in handy to get us and keep us moving. The first time you can do all that in a 2wd drive car....I'll switch.
For the last 5 years our other vehicle is an AWD minivan with Blizzaks in the winter and it's a tractor in the snow. I'm a big fan of snow tires but given the choice between snows and 4wd....I'll take 4wd every time. I just put new tires on my truck and went with a M+S rated AT tire. Should suit me just fine...we'll see next week