Winter tires are no help, for instance, when you're on what amounts to a sheet of ice.
They're also no help when you're in 2 feet of snow.
They're a big help at the margins, and it's definitely worth the investment in many, many cases, but they're absolutely no substitute for sufficient road treatment.
And again, yes, they help substantially in 2 feet of snow.
I agree that properly treated roads are necessary, but we treat roads for the lowest common denominator. If we as a population properly prepared (say that three times fast) for poor road conditions, we and our environment would be way better off.
Did the experience suck hard? It really did. I happened to get really lucky, and there was no one around, and I just ended up spinning around and pointing the wrong way, so I very carefully turned back around and went on my way.
But however much they may help, trying to claim that winter tires are good enough that we can use them instead of proper road treatments is irresponsible and dangerous. And I say this as someone who is extremely upset at the environmental toll standard road salt takes every winter.