Maybe they do for some people, but not in my experience. I get the impression (perhaps incorrectly) that the people who report troubles just find one gear and stick with it for miles and miles, and then are surprised it's stuck there by icy build-up.

I run full fenders with mudflaps, which keeps a lot of crap out of the drivetrain to begin with. I also run close-ratio cassettes and shift frequently, due to the stop-and-go nature of my route. That keeps the cables and RD freed-up and minimizes build-up on the cassette.

But also remember that my commutes are short (about 5 miles, 8 km) and I park indoors at both ends. Maybe that helps too, I dunno.